- 23 Mar, 2020 40 commits
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Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero." [1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by:Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by:
David Sterba <dsterba@suse.com> Signed-off-by:
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Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero." [1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero." [1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Madhuparna Bhowmik authored
The space_info list is normally RCU protected and should be traversed with rcu_read_lock held. There's a warning [29.104756] WARNING: suspicious RCU usage [29.105046] 5.6.0-rc4-next-20200305 #1 Not tainted [29.105231] ----------------------------- [29.105401] fs/btrfs/block-group.c:2011 RCU-list traversed in non-reader section!! pointing out that the locking is missing in btrfs_read_block_groups. However this is not necessary as the list traversal happens at mount time when there's no other thread potentially accessing the list. To fix the warning and for consistency let's add the RCU lock/unlock, the code won't be affected much as it's doing some lightweight operations. Reported-by:
Guenter Roeck <linux@roeck-us.net> Signed-off-by:
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com> Reviewed-by:
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Nikolay Borisov authored
No need to add a level of indirection for hiding a simple 'if'. Open code insert_extent_backref in its sole caller. No functional changes. Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Signed-off-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Nikolay Borisov authored
relocate_tree_blocks calls get_tree_block_key for a block iff that block has its ->key_ready equal false. Thus the BUG_ON in the latter function cannot ever be triggered so remove it. Reviewed-by:
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David Sterba authored
The validation follows the same steps for all three block group types, the existing helper validate_convert_profile can be enhanced and do more of the common things. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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David Sterba authored
Now that csum_tree_block is not returning any errors, we can make csum_tree_block return void and simplify callers. Reviewed-by:
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David Sterba authored
Thw whole point of csum_tree_block is to iterate over all extent buffer pages and pass it to checksumming functions. The bytes where checksum is stored must be skipped, thus map_private_extent_buffer. This complicates further offset calculations. As the first page will be always present, checksum the relevant bytes unconditionally and then do a simple iteration over the remaining pages. Reviewed-by:
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David Sterba authored
There's an unnecessary indirection in the checksum definition table, pointer and the string itself. The strings are short and the overall size of one entry is now 24 bytes. Reviewed-by:
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Nikolay Borisov authored
Having btrfs_alloc_chunk doesn't bring any value since it encapsulates a lockdep assert and a call to find_next_chunk. Simply rename the internal __btrfs_alloc_chunk function to the public one and remove it's 2nd parameter as all callers always pass the return value of find_next_chunk. Finally, migrate the call to lockdep_assert_held so as to not lose the check. Signed-off-by:
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Josef Bacik authored
I noticed while running my snapshot torture test that we were getting a lot of metadata chunks allocated with very little actually used. Digging into this we would commit the transaction, still not have enough space, and then force a chunk allocation. I noticed that we were barely flushing any delalloc at all, despite the fact that we had around 13gib of outstanding delalloc reservations. It turns out this is because of our btrfs_calc_reclaim_metadata_size() calculation. It _only_ takes into account the outstanding ticket sizes, which isn't the whole story. In this particular workload we're slowly filling up the disk, which means our overcommit space will suddenly become a lot less, and our outstanding reservations will be well more than what we can handle. However we are only flushing based on our ticket size, which is much less than we need to actually reclaim. So fix btrfs_calc_reclaim_metadata_size() to take into account the overage in the case that we've gotten less available space suddenly. This makes it so we attempt to reclaim a lot more delalloc space, which allows us to make our reservations and we no longer are allocating a bunch of needless metadata chunks. CC: stable@vger.kernel.org # 4.4+ Signed-off-by:
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Filipe Manana authored
During unmount we can have a job from the delayed inode items work queue still running, that can lead to at least two bad things: 1) A crash, because the worker can try to create a transaction just after the fs roots were freed; 2) A transaction leak, because the worker can create a transaction before the fs roots are freed and just after we committed the last transaction and after we stopped the transaction kthread. A stack trace example of the crash: [79011.691214] kernel BUG at lib/radix-tree.c:982! [79011.692056] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [79011.693180] CPU: 3 PID: 1394 Comm: kworker/u8:2 Tainted: G W 5.6.0-rc2-btrfs-next-54 #2 (...) [79011.696789] Workqueue: btrfs-delayed-meta btrfs_work_helper [btrfs] [79011.697904] RIP: 0010:radix_tree_tag_set+0xe7/0x170 (...) [79011.702014] RSP: 0018:ffffb3c84a317ca0 EFLAGS: 00010293 [79011.702949] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [79011.704202] RDX: ffffb3c84a317cb0 RSI: ffffb3c84a317ca8 RDI: ffff8db3931340a0 [79011.705463] RBP: 0000000000000005 R08: 0000000000000005 R09: ffffffff974629d0 [79011.706756] R10: ffffb3c84a317bc0 R11: 0000000000000001 R12: ffff8db393134000 [79011.708010] R13: ffff8db3931340a0 R14: ffff8db393134068 R15: 0000000000000001 [79011.709270] FS: 0000000000000000(0000) GS:ffff8db3b6a00000(0000) knlGS:0000000000000000 [79011.710699] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [79011.711710] CR2: 00007f22c2a0a000 CR3: 0000000232ad4005 CR4: 00000000003606e0 [79011.712958] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [79011.714205] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [79011.715448] Call Trace: [79011.715925] record_root_in_trans+0x72/0xf0 [btrfs] [79011.716819] btrfs_record_root_in_trans+0x4b/0x70 [btrfs] [79011.717925] start_transaction+0xdd/0x5c0 [btrfs] [79011.718829] btrfs_async_run_delayed_root+0x17e/0x2b0 [btrfs] [79011.719915] btrfs_work_helper+0xaa/0x720 [btrfs] [79011.720773] process_one_work+0x26d/0x6a0 [79011.721497] worker_thread+0x4f/0x3e0 [79011.722153] ? process_one_work+0x6a0/0x6a0 [79011.722901] kthread+0x103/0x140 [79011.723481] ? kthread_create_worker_on_cpu+0x70/0x70 [79011.724379] ret_from_fork+0x3a/0x50 (...) The following diagram shows a sequence of steps that lead to the crash during ummount of the filesystem: CPU 1 CPU 2 CPU 3 btrfs_punch_hole() btrfs_btree_balance_dirty() btrfs_balance_delayed_items() --> sees fs_info->delayed_root->items with value 200, which is greater than BTRFS_DELAYED_BACKGROUND (128) and smaller than BTRFS_DELAYED_WRITEBACK (512) btrfs_wq_run_delayed_node() --> queues a job for fs_info->delayed_workers to run btrfs_async_run_delayed_root() btrfs_async_run_delayed_root() --> job queued by CPU 1 --> starts picking and running delayed nodes from the prepare_list list close_ctree() btrfs_delete_unused_bgs() btrfs_commit_super() btrfs_join_transaction() --> gets transaction N btrfs_commit_transaction(N) --> set transaction state to TRANTS_STATE_COMMIT_START btrfs_first_prepared_delayed_node() --> picks delayed node X through the prepared_list list btrfs_run_delayed_items() btrfs_first_delayed_node() --> also picks delayed node X but through the node_list list __btrfs_commit_inode_delayed_items() --> runs all delayed items from this node and drops the node's item count to 0 through call to btrfs_release_delayed_inode() --> finishes running any remaining delayed nodes --> finishes transaction commit --> stops cleaner and transaction threads btrfs_free_fs_roots() --> frees all roots and removes them from the radix tree fs_info->fs_roots_radix btrfs_join_transaction() start_transaction() btrfs_record_root_in_trans() record_root_in_trans() radix_tree_tag_set() --> crashes because the root is not in the radix tree anymore If the worker is able to call btrfs_join_transaction() before the unmount task frees the fs roots, we end up leaking a transaction and all its resources, since after the call to btrfs_commit_super() and stopping the transaction kthread, we don't expect to have any transaction open anymore. When this situation happens the worker has a delayed node that has no more items to run, since the task calling btrfs_run_delayed_items(), which is doing a transaction commit, picks the same node and runs all its items first. We can not wait for the worker to complete when running delayed items through btrfs_run_delayed_items(), because we call that function in several phases of a transaction commit, and that could cause a deadlock because the worker calls btrfs_join_transaction() and the task doing the transaction commit may have already set the transaction state to TRANS_STATE_COMMIT_DOING. Also it's not possible to get into a situation where only some of the items of a delayed node are added to the fs/subvolume tree in the current transaction and the remaining ones in the next transaction, because when running the items of a delayed inode we lock its mutex, effectively waiting for the worker if the worker is running the items of the delayed node already. Since this can only cause issues when unmounting a filesystem, fix it in a simple way by waiting for any jobs on the delayed workers queue before calling btrfs_commit_supper() at close_ctree(). This works because at this point no one can call btrfs_btree_balance_dirty() or btrfs_balance_delayed_items(), and if we end up waiting for any worker to complete, btrfs_commit_super() will commit the transaction created by the worker. CC: stable@vger.kernel.org # 4.4+ Signed-off-by:Filipe Manana <fdmanana@suse.com> Reviewed-by:
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Naohiro Aota authored
This function finally factor out prepare_allocation() form find_free_extent(). This function is called before the allocation loop and a specific allocator function like prepare_allocation_clustered() should initialize their private information and can set proper hint_byte to indicate where to start the allocation with. Reviewed-by:
Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by:
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Naohiro Aota authored
LOOP_NO_EMPTY_SIZE is solely dedicated for clustered allocation. So, we can skip this stage and give up the allocation. Signed-off-by:
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Naohiro Aota authored
Factor out chunk_allocation_failed() from find_free_extent_update_loop(). This function is called when it failed to allocate a chunk. The function can modify "ffe_ctl->loop" and return 0 to continue with the next stage. Or, it can return -ENOSPC to give up here. Reviewed-by:
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Naohiro Aota authored
Now that, we don't use last_ptr and use_cluster in the function. Drop these arguments from it. Reviewed-by:
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Naohiro Aota authored
Factor out found_extent() from find_free_extent_update_loop(). This function is called when a proper extent is found and before returning from find_free_extent(). Hook functions like found_extent_clustered() should save information for a next allocation. Reviewed-by:
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Naohiro Aota authored
Factor out release_block_group() from find_free_extent(). This function is called when it gives up an allocation from a block group. Each allocation policy should reset its information for an allocation in the next block group. Reviewed-by:
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Naohiro Aota authored
Now that, find_free_extent_clustered() and find_free_extent_unclustered() can access "last_ptr" from the "clustered" variable, we can drop it from the arguments. Reviewed-by:
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Naohiro Aota authored
Factor out do_allocation() from find_free_extent(). This function do an actual extent allocation in a given block group. The ffe_ctl->policy is used to determine the actual allocator function to use. Reviewed-by:
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Naohiro Aota authored
Move "last_ptr" and "use_cluster" into struct find_free_extent_ctl, so that hook functions for clustered allocator can use these variables. Reviewed-by:
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Naohiro Aota authored
This commit moves hint_byte into find_free_extent_ctl, so that we can modify the hint_byte in the other functions. This will help us split find_free_extent further. This commit also renames the function argument "hint_byte" to "hint_byte_orig" to avoid misuse. Reviewed-by:
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Naohiro Aota authored
This commit introduces extent allocation policy for btrfs. This policy controls how btrfs allocate an extents from block groups. There is no functional change introduced with this commit. Reviewed-by:
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Naohiro Aota authored
Currently, we ignore a device whose available space is less than "BTRFS_STRIPE_LEN * dev_stripes". This is a lower limit for current allocation policy (to maximize the number of stripes). This commit parameterizes dev_extent_min, so that other policies can set their own lower limitat to ignore a device with insufficient space. Reviewed-by:
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Naohiro Aota authored
Factor out create_chunk() from __btrfs_alloc_chunk(). This function finally creates a chunk. There is no functional changes. Reviewed-by:
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Naohiro Aota authored
Factor out decide_stripe_size() from __btrfs_alloc_chunk(). This function calculates the actual stripe size to allocate. decide_stripe_size() handles the common case to round down the 'ndevs' to 'devs_increment' and check the upper and lower limitation of 'ndevs'. decide_stripe_size_regular() decides the size of a stripe and the size of a chunk. The policy is to maximize the number of stripes. This commit has no functional changes. Reviewed-by:
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Naohiro Aota authored
Factor out gather_device_info() from __btrfs_alloc_chunk(). This function iterates over devices list and gather information about devices. This commit also introduces "max_avail" and "dev_extent_min" to fold the same calculation to one variable. This commit has no functional changes. Reviewed-by:
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Naohiro Aota authored
Factor out init_alloc_chunk_ctl() from __btrfs_alloc_chunk(). This function initialises parameters of "struct alloc_chunk_ctl" for allocation. init_alloc_chunk_ctl() handles a common part of the initialisation to load the RAID parameters from btrfs_raid_array. init_alloc_chunk_ctl_policy_regular() decides some parameters for its allocation. The last "else" case in the original code is moved to __btrfs_alloc_chunk() to handle the error case in the common code. Replace the BUG_ON with ASSERT() and error return at the same time. Reviewed-by:
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Naohiro Aota authored
Introduce "struct alloc_chunk_ctl" to wrap needed parameters for the chunk allocation. This will be used to split __btrfs_alloc_chunk() into smaller functions. This commit folds a number of local variables in __btrfs_alloc_chunk() into one "struct alloc_chunk_ctl ctl". There is no functional change. Reviewed-by:
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Naohiro Aota authored
Factor out two functions from find_free_dev_extent_start(). dev_extent_search_start() decides the starting position of the search. dev_extent_hole_check() checks if a hole found is suitable for device extent allocation. These functions also have the switch-cases to change the allocation behavior depending on the policy. Reviewed-by:
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Naohiro Aota authored
Introduce chunk allocation policy for btrfs. This policy controls how chunks and device extents are allocated from devices. Reviewed-by:
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Naohiro Aota authored
Do not BUG_ON() when an invalid profile is passed to __btrfs_alloc_chunk(). Instead return -EINVAL with ASSERT() to catch a bug in the development stage. Suggested-by:
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Naohiro Aota authored
While the "full_search" variable defined in find_free_extent() is bool, but the full_search argument of find_free_extent_update_loop() is defined as int. Let's trivially fix the argument type. Reviewed-by:
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Qu Wenruo authored
After the previous patch, qgroup_rescan_running is protected by btrfs_fs_info::qgroup_rescan_lock, thus no need for the extra spinlock. Suggested-by:
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Qu Wenruo authored
[BUG] There are some reports about btrfs wait forever to unmount itself, with the following call trace: INFO: task umount:4631 blocked for more than 491 seconds. Tainted: G X 5.3.8-2-default #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. umount D 0 4631 3337 0x00000000 Call Trace: ([<00000000174adf7a>] __schedule+0x342/0x748) [<00000000174ae3ca>] schedule+0x4a/0xd8 [<00000000174b1f08>] schedule_timeout+0x218/0x420 [<00000000174af10c>] wait_for_common+0x104/0x1d8 [<000003ff804d6994>] btrfs_qgroup_wait_for_completion+0x84/0xb0 [btrfs] [<000003ff8044a616>] close_ctree+0x4e/0x380 [btrfs] [<0000000016fa3136>] generic_shutdown_super+0x8e/0x158 [<0000000016fa34d6>] kill_anon_super+0x26/0x40 [<000003ff8041ba88>] btrfs_kill_super+0x28/0xc8 [btrfs] [<0000000016fa39f8>] deactivate_locked_super+0x68/0x98 [<0000000016fcb198>] cleanup_mnt+0xc0/0x140 [<0000000016d6a846>] task_work_run+0xc6/0x110 [<0000000016d04f76>] do_notify_resume+0xae/0xb8 [<00000000174b30ae>] system_call+0xe2/0x2c8 [CAUSE] The problem happens when we have called qgroup_rescan_init(), but not queued the worker. It can be caused mostly by error handling. Qgroup ioctl thread | Unmount thread ----------------------------------------+----------------------------------- | btrfs_qgroup_rescan() | |- qgroup_rescan_init() | | |- qgroup_rescan_running = true; | | | |- trans = btrfs_join_transaction() | | Some error happened | | | |- btrfs_qgroup_rescan() returns error | But qgroup_rescan_running == true; | | close_ctree() | |- btrfs_qgroup_wait_for_completion() | |- running == true; | |- wait_for_completion(); btrfs_qgroup_rescan_worker is never queued, thus no one is going to wake up close_ctree() and we get a deadlock. All involved qgroup_rescan_init() callers are: - btrfs_qgroup_rescan() The example above. It's possible to trigger the deadlock when error happened. - btrfs_quota_enable() Not possible. Just after qgroup_rescan_init() we queue the work. - btrfs_read_qgroup_config() It's possible to trigger the deadlock. It only init the work, the work queueing happens in btrfs_qgroup_rescan_resume(). Thus if error happened in between, deadlock is possible. We shouldn't set fs_info->qgroup_rescan_running just in qgroup_rescan_init(), as at that stage we haven't yet queued qgroup rescan worker to run. [FIX] Set qgroup_rescan_running before queueing the work, so that we ensure the rescan work is queued when we wait for it. Fixes: 8d9eddad ("Btrfs: fix qgroup rescan worker initialization") Signed-off-by:Jeff Mahoney <jeffm@suse.com> [ Change subject and cause analyse, use a smaller fix ] Signed-off-by:
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Andy Shevchenko authored
uuid_le_gen() is no used anymore, remove it for good. Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by:
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Andy Shevchenko authored
There are new types and helpers that are supposed to be used in new code. As a preparation to get rid of legacy types and API functions do the conversion here. Reviewed-by:
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Andy Shevchenko authored
In some cases we would like to generate a GUID and export it. Though it would require either casting to internal kernel types or an intermediate buffer. Instead we may achieve this by supplying a pointer to raw buffer and make a complimentary API to existing one for UUIDs. Reviewed-by:
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Andy Shevchenko authored
Sometimes we may need to import UUID from or export to the raw buffer, which is provided outside of kernel and can't be declared as UUID type. With current API this operation will require an explicit casting to one of UUID types and length, that is always a constant derived as sizeof the certain UUID type. Provide a helpful set of inline helpers to minimize developer's effort in the cases when raw buffers are involved. Suggested-by:
David Sterba <dsterba@suse.cz> Acked-by:
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