- 26 Jun, 2015 40 commits
-
-
Joe Perches authored
Perl 5.22 emits a deprecated message when "\C" is used in a regex. Perl 5.24 will disallow it altogether. Fix it by using [A-Z] instead of \C. Signed-off-by:
Joe Perches <joe@perches.com> Reported-by:
Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Joe Perches authored
Section headers can be quite long and some are very long and duplicated for many initial characters. The current maximum length emitted for a section header is 20 bytes (or 17 bytes then ... when the section header length is > 20). Change that length to 50 so more of the section is shown. Example new output: $ ./scripts/get_maintainer.pl -f drivers/net/ethernet/broadcom/bnx2x/ Ariel Elior <ariel.elior@qlogic.com> (supporter:BROADCOM BNX2X 10 GIGABIT ETHERNET DRIVER) netdev@vger.kernel.org (open list:BROADCOM BNX2X 10 GIGABIT ETHERNET DRIVER) linux-kernel@vger.kernel.org (open list) Old: $ ./scripts/get_maintainer.pl -f drivers/net/ethernet/broadcom/bnx2x/ Ariel Elior <ariel.elior@qlogic.com> (supporter:BROADCOM BNX2X 10...) netdev@vger.kernel.org (open list:BROADCOM BNX2X 10...) linux-kernel@vger.kernel.org (open list) Signed-off-by:
-
Joe Perches authored
Some people prefer not to be cc'd on patches. Add an ability to have a file (.get_maintainer.ignore) with names and email addresses that are excluded from being listed except when specifically listed as a maintainer in a section. Signed-off-by:
-
Vasily Averin authored
Patch fixes drawbacks in heck_syslog_permissions() noticed by AKPM: "from_file handling makes me cry. That's not a boolean - it's an enumerated value with two values currently defined. But the code in check_syslog_permissions() treats it as a boolean and also hardwires the knowledge that SYSLOG_FROM_PROC == 1 (or == `true`). And the name is wrong: it should be called from_proc to match SYSLOG_FROM_PROC." Signed-off-by:
Vasily Averin <vvs@virtuozzo.com> Cc: Kees Cook <keescook@chromium.org> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Eric Paris <eparis@redhat.com> Signed-off-by:
-
Vasily Averin authored
The final version of commit 637241a9 ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg") lost few hooks, as result security_syslog() are processed incorrectly: - open of /dev/kmsg checks syslog access permissions by using check_syslog_permissions() where security_syslog() is not called if dmesg_restrict is set. - syslog syscall and /proc/kmsg calls do_syslog() where security_syslog can be executed twice (inside check_syslog_permissions() and then directly in do_syslog()) With this patch security_syslog() is called once only in all syslog-related operations regardless of dmesg_restrict value. Fixes: 637241a9 ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg") Signed-off-by:
-
Tejun Heo authored
printk logbuf keeps various metadata and optional key=value dictionary for structured messages, both of which are stripped when messages are handed to regular console drivers. It can be useful to have this metadata and dictionary available to netconsole consumers. This obviously makes logging via netconsole more complete and the sequence number in particular is useful in environments where messages may be lost or reordered in transit - e.g. when netconsole is used to collect messages in a large cluster where packets may have to travel congested hops to reach the aggregator. The lost and reordered messages can easily be identified and handled accordingly using the sequence numbers. printk recently added extended console support which can be selected by setting CON_EXTENDED flag. From console driver side, not much changes. The only difference is that the text passed to the write callback is formatted the same way as /dev/kmsg. This patch implements extended console support for netconsole which can be enabled by either prepending "+" to a netconsole boot param entry or echoing 1 to "extended" file in configfs. When enabled, netconsole transmits extended log messages with headers identical to /dev/kmsg output. There's one complication due to message fragments. netconsole limits the maximum message size to 1k and messages longer than that are split into multiple fragments. As all extended console messages should carry matching headers and be uniquely identifiable, each extended message fragment carries full copy of the metadata and an extra header field to identify the specific fragment. The optional header is of the form "ncfrag=OFF/LEN" where OFF is the byte offset into the message body and LEN is the total length. To avoid unnecessarily making printk format extended messages, Extended netconsole is registered with printk when the first extended netconsole is configured. Signed-off-by:
Tejun Heo <tj@kernel.org> Cc: David Miller <davem@davemloft.net> Cc: Kay Sievers <kay@vrfy.org> Cc: Petr Mladek <pmladek@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by:
-
Tejun Heo authored
Currently, each dynamic netconsole_target uses its own separate mutex to synchronize the configuration operations. This patch replaces the per-netconsole_target mutexes with a single mutex - dynamic_netconsole_mutex. The reduced granularity doesn't hurt anything, the code is minutely simpler and this'd allow adding operations which should be synchronized across all dynamic netconsoles. Signed-off-by:
-
Tejun Heo authored
netconsole uses both bool and int for boolean values. Let's convert nt->enabled to bool for consistency. Signed-off-by:
-
Tejun Heo authored
write_msg() grabs target_list_lock and walks target_list invoking netpool_send_udp() on each target. Curiously, it protects each iteration with netconsole_target_get/put() even though it never releases target_list_lock which protects all the members. While this doesn't harm anything, it doesn't serve any purpose either. The items on the list can't go away while target_list_lock is held. Remove the unnecessary get/put pair. Signed-off-by:
-
Tejun Heo authored
printk log_buf keeps various metadata for each message including its sequence number and timestamp. The metadata is currently available only through /dev/kmsg and stripped out before passed onto console drivers. We want this metadata to be available to console drivers too so that console consumers can get full information including the metadata and dictionary, which among other things can be used to detect whether messages got lost in transit. This patch implements support for extended console drivers. Consoles can indicate that they want extended messages by setting the new CON_EXTENDED flag and they'll be fed messages formatted the same way as /dev/kmsg. "<level>,<sequnum>,<timestamp>,<contflag>;<message text>\n" If extended consoles exist, in-kernel fragment assembly is disabled. This ensures that all messages emitted to consoles have full metadata including sequence number. The contflag carries enough information to reassemble the fragments from the reader side trivially. Note that this only affects /dev/kmsg. Regular console and /proc/kmsg outputs are not affected by this change. * Extended message formatting for console drivers is enabled iff there are registered extended consoles. * Comment describing /dev/kmsg message format updated to add missing contflag field and help distinguishing variable from verbatim terms. Signed-off-by:
Petr Mladek <pmladek@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by:
-
Tejun Heo authored
The extended message formatting used for /dev/kmsg will be used implement extended consoles. Factor out msg_print_ext_header() and msg_print_ext_body() from devkmsg_read(). This is pure restructuring. Signed-off-by:
-
Tejun Heo authored
This patchset updates netconsole so that it can emit messages with the same header as used in /dev/kmsg which gives neconsole receiver full log information which enables things like structured logging and detection of lost messages. This patch (of 7): devkmsg_read() uses 8k buffer and assumes that the formatted output message won't overrun which seems safe given LOG_LINE_MAX, the current use of dict and the escaping method being used; however, we're planning to use devkmsg formatting wider and accounting for the buffer size properly isn't that complicated. This patch defines CONSOLE_EXT_LOG_MAX as 8192 and updates devkmsg_read() so that it limits output accordingly. Signed-off-by:
-
Colin Ian King authored
The KERN_INFO prefix is being prepended to KERN_DEBUG when using the dprink macro, Remove it as it is extraneous since we are printing the message out as debug via dprintk(). Fixes smatch warning: drivers/misc/altera-stapl/altera.c:2454 altera_init() warn: KERN_* level not at start of string Signed-off-by:
Colin Ian King <colin.king@canonical.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Igor M. Liplianin <liplianin@netup.ru> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Signed-off-by:
-
Josh Triplett authored
clone has some of the quirkiest syscall handling in the kernel, with a pile of special cases, historical curiosities, and architecture-specific calling conventions. In particular, clone with CLONE_SETTLS accepts a parameter "tls" that the C entry point completely ignores and some assembly entry points overwrite; instead, the low-level arch-specific code pulls the tls parameter out of the arch-specific register captured as part of pt_regs on entry to the kernel. That's a massive hack, and it makes the arch-specific code only work when called via the specific existing syscall entry points; because of this hack, any new clone-like system call would have to accept an identical tls argument in exactly the same arch-specific position, rather than providing a unified system call entry point across architectures. The first patch allows architectures to handle the tls argument via normal C parameter passing, if they opt in by selecting HAVE_COPY_THREAD_TLS. The second patch makes 32-bit and 64-bit x86 opt into this. These two patches came out of the clone4 series, which isn't ready for this merge window, but these first two cleanup patches were entirely uncontroversial and have acks. I'd like to go ahead and submit these two so that other architectures can begin building on top of this and opting into HAVE_COPY_THREAD_TLS. However, I'm also happy to wait and send these through the next merge window (along with v3 of clone4) if anyone would prefer that. This patch (of 2): clone with CLONE_SETTLS accepts an argument to set the thread-local storage area for the new thread. sys_clone declares an int argument tls_val in the appropriate point in the argument list (based on the various CLONE_BACKWARDS variants), but doesn't actually use or pass along that argument. Instead, sys_clone calls do_fork, which calls copy_process, which calls the arch-specific copy_thread, and copy_thread pulls the corresponding syscall argument out of the pt_regs captured at kernel entry (knowing what argument of clone that architecture passes tls in). Apart from being awful and inscrutable, that also only works because only one code path into copy_thread can pass the CLONE_SETTLS flag, and that code path comes from sys_clone with its architecture-specific argument-passing order. This prevents introducing a new version of the clone system call without propagating the same architecture-specific position of the tls argument. However, there's no reason to pull the argument out of pt_regs when sys_clone could just pass it down via C function call arguments. Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt into, and a new copy_thread_tls that accepts the tls parameter as an additional unsigned long (syscall-argument-sized) argument. Change sys_clone's tls argument to an unsigned long (which does not change the ABI), and pass that down to copy_thread_tls. Architectures that don't opt into copy_thread_tls will continue to ignore the C argument to sys_clone in favor of the pt_regs captured at kernel entry, and thus will be unable to introduce new versions of the clone syscall. Patch co-authored by Josh Triplett and Thiago Macieira. Signed-off-by:
Josh Triplett <josh@joshtriplett.org> Acked-by:
Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thiago Macieira <thiago.macieira@intel.com> Signed-off-by:
-
Joe Perches authored
Commit 38764884 ("include/stddef.h: Move offsetofend() from vfio.h to a generic kernel header") added offsetofend outside the normal include #ifndef/#endif guard. Move it inside. Miscellanea: o remove unnecessary blank line o standardize offsetof macros whitespace style Signed-off-by:
-
Kees Cook authored
To avoid having xenotime bounce when things like get_maintainers gives me addresses, add Randy's current address. Signed-off-by:
Kees Cook <keescook@chromium.org> Acked-by:
Randy Dunlap <rdunlap@infradead.org> Cc: Joe Perches <joe@perches.com> Signed-off-by:
-
Pratyush Anand authored
Mohit's email-id doesn't exist anymore as he has left the company. Replace ST's id with mohit.kumar.dhaka@gmail.com. Signed-off-by:
Pratyush Anand <pratyush.anand@gmail.com> Cc: Mohit Kumar <mohit.kumar.dhaka@gmail.com> Signed-off-by:
-
Pratyush Anand authored
pratyush.anand@st.com email-id doesn't exist anymore as I have left the company. Replace ST's id with pratyush.anand@gmail.com. Signed-off-by:
-
Daniel Borkmann authored
Cleanup commit 73679e50 ("compiler-intel.h: Remove duplicate definition") removed the double definition of __memory_barrier() intrinsics. However, in doing so, it also removed the preceding #undef barrier by accident, meaning, the actual barrier() macro from compiler-gcc.h with inline asm is still in place as __GNUC__ is provided. Subsequently, barrier() can never be defined as __memory_barrier() from compiler.h since it already has a definition in place and if we trust the comment in compiler-intel.h, ecc doesn't support gcc specific asm statements. I don't have an ecc at hand (unsure if that's still used in the field?) and only found this by accident during code review, a revert of that cleanup would be simplest option. Fixes: 73679e50 ("compiler-intel.h: Remove duplicate definition") Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Reviewed-by:
Pranith Kumar <bobby.prani@gmail.com> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: mancha security <mancha1@zoho.com> Signed-off-by:
-
Joe Perches authored
As gcc major version numbers are going to advance rather rapidly in the future, there's no real value in separate files for each compiler version. Deduplicate some of the macros #defined in each file too. Neaten comments using normal kernel commenting style. Signed-off-by:
-
Joe Perches authored
- Move the inline and noinline blocks together - Comment neatening - Alignment of __attribute__ uses - Consistent naming of __must_be_array macro argument - Multiline macro neatening Signed-off-by:
-
Iago López Galeiras authored
Commit 81841161 ("fs, proc: introduce /proc/<pid>/task/<tid>/children entry") introduced the children entry for checkpoint restore and the file is only available on kernels configured with CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE. This is available in most distributions (Fedora, Debian, Ubuntu, CoreOS) because they usually enable CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE. But Arch does not enable CONFIG_EXPERT or CONFIG_CHECKPOINT_RESTORE. However, the children proc file is useful outside of checkpoint restore. I would like to use it in rkt. The rkt process exec() another program it does not control, and that other program will fork()+exec() a child process. I would like to find the pid of the child process from an external tool without iterating in /proc over all processes to find which one has a parent pid equal to rkt. This commit introduces CONFIG_PROC_CHILDREN and makes CONFIG_CHECKPOINT_RESTORE select it. This allows enabling /proc/<pid>/task/<tid>/children without needing to enable CONFIG_CHECKPOINT_RESTORE and CONFIG_EXPERT. Alban tested that /proc/<pid>/task/<tid>/children is present when the kernel is configured with CONFIG_PROC_CHILDREN=y but without CONFIG_CHECKPOINT_RESTORE Signed-off-by:
Iago López Galeiras <iago@endocode.com> Tested-by:
Alban Crequy <alban@endocode.com> Reviewed-by:
Cyrill Gorcunov <gorcunov@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Djalal Harouni <djalal@endocode.com> Signed-off-by:
-
Alexey Dobriyan authored
/proc/$PID/cmdline truncates output at PAGE_SIZE. It is easy to see with $ cat /proc/self/cmdline $(seq 1037) 2>/dev/null However, command line size was never limited to PAGE_SIZE but to 128 KB and relatively recently limitation was removed altogether. People noticed and ask questions: http://stackoverflow.com/questions/199130/how-do-i-increase-the-proc-pid-cmdline-4096-byte-limit seq file interface is not OK, because it kmalloc's for whole output and open + read(, 1) + sleep will pin arbitrary amounts of kernel memory. To not do that, limit must be imposed which is incompatible with arbitrary sized command lines. I apologize for hairy code, but this it direct consequence of command line layout in memory and hacks to support things like "init [3]". The loops are "unrolled" otherwise it is either macros which hide control flow or functions with 7-8 arguments with equal line count. There should be real setproctitle(2) or something. [akpm@linux-foundation.org: fix a billion min() warnings] Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Tested-by:
Jarod Wilson <jarod@redhat.com> Acked-by:
-
Alexey Dobriyan authored
Individual prctl(PR_SET_MM_*) calls do some checking to maintain a consistent view of mm->arg_start et al fields, but not enough. In particular PR_SET_MM_ARG_START/PR_SET_MM_ARG_END/ R_SET_MM_ENV_START/ PR_SET_MM_ENV_END only check that the address lies in an existing VMA, but don't check that the start address is lower than the end address _at all_. Consolidate all consistency checks, so there will be no difference in the future between PR_SET_MM_MAP and individual PR_SET_MM_* calls. The program below makes both ARGV and ENVP areas be reversed. It makes /proc/$PID/cmdline show garbage (it doesn't oops by luck). #include <sys/mman.h> #include <sys/prctl.h> #include <unistd.h> enum {PAGE_SIZE=4096}; int main(void) { void *p; p = mmap(NULL, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); #define PR_SET_MM 35 #define PR_SET_MM_ARG_START 8 #define PR_SET_MM_ARG_END 9 #define PR_SET_MM_ENV_START 10 #define PR_SET_MM_ENV_END 11 prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long)p + PAGE_SIZE - 1, 0, 0); prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long)p, 0, 0); prctl(PR_SET_MM, PR_SET_MM_ENV_START, (unsigned long)p + PAGE_SIZE - 1, 0, 0); prctl(PR_SET_MM, PR_SET_MM_ENV_END, (unsigned long)p, 0, 0); pause(); return 0; } [akpm@linux-foundation.org: tidy code, tweak comment] Signed-off-by: -
Akinobu Mita authored
This replaces the plain loop over the sglist array with for_each_sg() macro which consists of sg_next() function calls. Since avr32 doesn't select ARCH_HAS_SG_CHAIN, it is not necessary to use for_each_sg() in order to loop over each sg element. But this can help find problems with drivers that do not properly initialize their sg tables when CONFIG_DEBUG_SG is enabled. Signed-off-by:
Akinobu Mita <akinobu.mita@gmail.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Acked-by:
Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by:
-
Akinobu Mita authored
This replaces the plain loop over the sglist array with for_each_sg() macro which consists of sg_next() function calls. Since frv doesn't select ARCH_HAS_SG_CHAIN, it is not necessary to use for_each_sg() in order to loop over each sg element. But this can help find problems with drivers that do not properly initialize their sg tables when CONFIG_DEBUG_SG is enabled. Signed-off-by:
-
Tobias Klauser authored
The function is not used anywhere in the tree (anymore) and this is the last remaining instance, so remove it. Signed-off-by:
Tobias Klauser <tklauser@distanz.ch> Cc: David Howells <dhowells@redhat.com> Signed-off-by:
-
Dan Streetman authored
Remove zpool_evict() helper function. As zbud is currently the only zpool implementation that supports eviction, add zpool and zpool_ops references to struct zbud_pool and directly call zpool_ops->evict(zpool, handle) on eviction. Currently zpool provides the zpool_evict helper which locks the zpool list lock and searches through all pools to find the specific one matching the caller, and call the corresponding zpool_ops->evict function. However, this is unnecessary, as the zbud pool can simply keep a reference to the zpool that created it, as well as the zpool_ops, and directly call the zpool_ops->evict function, when it needs to evict a page. This avoids a spinlock and list search in zpool for each eviction. Signed-off-by:
Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by:
-
Dan Streetman authored
Change the pr_info() calls to pr_debug(). There's no need for the extra verbosity in the log. Also change the msg formats to be consistent. Signed-off-by:
-
Dan Streetman authored
Change the "enabled" parameter to be configurable at runtime. Remove the enabled check from init(), and move it to the frontswap store() function; when enabled, pages will be stored, and when disabled, pages won't be stored. This is almost identical to Seth's patch from 2 years ago: http://lkml.iu.edu/hypermail/linux/kernel/1307.2/04289.html [akpm@linux-foundation.org: tweak documentation] Signed-off-by:
Seth Jennings <sjennings@variantweb.net> Signed-off-by:
-
Sergey Senozhatsky authored
Improvement idea by Marcin Jabrzyk. comp_algorithm_store() silently accepts any supplied algorithm name, because zram performs algorithm availability check later, during the device configuration phase in disksize_store() and emits the following error: "zram: Cannot initialise %s compressing backend" this error line is somewhat generic and, besides, can indicate a failed attempt to allocate compression backend's working buffers. add algorithm availability check to comp_algorithm_store(): echo lzz > /sys/block/zram0/comp_algorithm -bash: echo: write error: Invalid argument Signed-off-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by:
Marcin Jabrzyk <m.jabrzyk@samsung.com> Acked-by:
Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by:
-
Sergey Senozhatsky authored
Supplied sysfs values sometimes contain new-line symbols (echo vs. echo -n), which we also copy as a compression algorithm name. it works fine when we lookup for compression algorithm, because we use sysfs_streq() which takes care of new line symbols. however, it doesn't look nice when we print compression algorithm name if zcomp_create() failed: zram: Cannot initialise LXZ compressing backend cut trailing new-line, so the error string will look like zram: Cannot initialise LXZ compressing backend we also now can replace sysfs_streq() in zcomp_available_show() with strcmp(). Signed-off-by: -
Sergey Senozhatsky authored
`bool locked' local variable tells us if we should perform zcomp_strm_release() or not (jumped to `out' label before zcomp_strm_find() occurred), which is equivalent to `zstrm' being or not being NULL. remove `locked' and check `zstrm' instead. Signed-off-by:
-
Sergey Senozhatsky authored
We currently don't support on-demand device creation. The one and only way to have N zram devices is to specify num_devices module parameter (default value: 1). IOW if, for some reason, at some point, user wants to have N + 1 devies he/she must umount all the existing devices, unload the module, load the module passing num_devices equals to N + 1. And do this again, if needed. This patch introduces zram control sysfs class, which has two sysfs attrs: - hot_add -- add a new zram device - hot_remove -- remove a specific (device_id) zram device hot_add sysfs attr is read-only and has only automatic device id assignment mode (as requested by Minchan Kim). read operation performed on this attr creates a new zram device and returns back its device_id or error status. Usage example: # add a new specific zram device cat /sys/class/zram-control/hot_add 2 # remove a specific zram device echo 4 > /sys/class/zram-control/hot_remove Returning zram_add() error code back to user (-ENOMEM in this case) cat /sys/class/zram-control/hot_add cat: /sys/class/zram-control/hot_add: Cannot allocate memory NOTE, there might be users who already depend on the fact that at least zram0 device gets always created by zram_init(). Preserve this behavior. [minchan@kernel.org: use zram->claim to avoid lockdep splat] Signed-off-by:
-
Sergey Senozhatsky authored
[ Original patch from Minchan Kim <minchan@kernel.org> ] Commit ba6b17d6 ("zram: fix umount-reset_store-mount race condition") introduced bdev->bd_mutex to protect a race between mount and reset. At that time, we don't have dynamic zram-add/remove feature so it was okay. However, as we introduce dynamic device feature, bd_mutex became trouble. CPU 0 echo 1 > /sys/block/zram<id>/reset -> kernfs->s_active(A) -> zram:reset_store->bd_mutex(B) CPU 1 echo <id> > /sys/class/zram/zram-remove ->zram:zram_remove: bd_mutex(B) -> sysfs_remove_group -> kernfs->s_active(A) IOW, AB -> BA deadlock The reason we are holding bd_mutex for zram_remove is to prevent any incoming open /dev/zram[0-9]. Otherwise, we could remove zram others already have opened. But it causes above deadlock problem. To fix the problem, this patch overrides block_device.open and it returns -EBUSY if zram asserts he claims zram to reset so any incoming open will be failed so we don't need to hold bd_mutex for zram_remove ayn more. This patch is to prepare for zram-add/remove feature. [sergey.senozhatsky@gmail.com: simplify reset_store()] Signed-off-by:
-
Sergey Senozhatsky authored
This patch prepares zram to enable on-demand device creation. zram_add() performs automatic device_id assignment and returns new device id (>= 0) or error code (< 0). Signed-off-by:
-
Sergey Senozhatsky authored
We don't have meta->tb_lock anymore and use meta table entry bit_spin_lock instead. update corresponding comment. Signed-off-by:
-
Sergey Senozhatsky authored
With dynamic device creation/removal (which will be introduced later in the series) printing num_devices in zram_init() will not make a lot of sense, as well as printing the number of destroyed devices in destroy_devices(). Print per-device action (added/removed) in zram_add() and zram_remove() instead. Example: [ 3645.259652] zram: Added device: zram5 [ 3646.152074] zram: Added device: zram6 [ 3650.585012] zram: Removed device: zram5 [ 3655.845584] zram: Added device: zram8 [ 3660.975223] zram: Removed device: zram6 Signed-off-by:
-
Sergey Senozhatsky authored
Limiting the number of zram devices to 32 (default max_num_devices value) is confusing, let's drop it. A user with 2TB or 4TB of RAM, for example, can request as many devices as he can handle. Signed-off-by:
-
Sergey Senozhatsky authored
This patch looks big, but basically it just moves code blocks. No functional changes. Our current code layout looks like a sandwitch. For example, a) between read/write handlers, we have update_used_max() helper function: static int zram_decompress_page static int zram_bvec_read static inline void update_used_max static int zram_bvec_write static int zram_bvec_rw b) RW request handlers __zram_make_request/zram_bio_discard are divided by sysfs attr reset_store() function and corresponding zram_reset_device() handler: static void zram_bio_discard static void zram_reset_device static ssize_t disksize_store static ssize_t reset_store static void __zram_make_request c) we first a bunch of sysfs read/store functions. then a number of one-liners, then helper functions, RW functions, sysfs functions, helper functions again, and so on. Reorganize layout to be more logically grouped (a brief description, `cat zram_drv.c | grep static` gives a bigger picture): -- one-liners: zram_test_flag/etc. -- helpers: is_partial_io/update_position/etc -- sysfs attr show/store functions + ZRAM_ATTR_RO() generated stats show() functions exception: reset and disksize store functions are required to be after meta() functions. because we do device create/destroy actions in these sysfs handlers. -- "mm" functions: meta get/put, meta alloc/free, page free static inline bool zram_meta_get static inline void zram_meta_put static void zram_meta_free static struct zram_meta *zram_meta_alloc static void zram_free_page -- a block of I/O functions static int zram_decompress_page static int zram_bvec_read static int zram_bvec_write static void zram_bio_discard static int zram_bvec_rw static void __zram_make_request static void zram_make_request static void zram_slot_free_notify static int zram_rw_page -- device contol: add/remove/init/reset functions (+zram-control class will sit here) static int zram_reset_device static ssize_t reset_store static ssize_t disksize_store static int zram_add static void zram_remove static int __init zram_init static void __exit zram_exit Signed-off-by:
-
