When an I/O completed with an error, we would call bio_endio twice
(once with -EIO and once with 0).  Found by inspection.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

THe device reports (in its capability register) how long it will take
to initialise.  If that time elapses before the ready bit becomes set,
conclude the device is broken and refuse to initialise it.  Log a nice
error message so the user knows why we did nothing.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

We need to clear the affinity mask before calling free_irq()
Reported-by: Shane Michael Matthews <shane.matthews@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

The arbitration field was extended by one bit, shifting the shutdown
notification bits by one.  Also, the SQ/CQ entry size was made
configurable for future extensions.
Reported-by: Paul Luse <paul.e.luse@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

The read and write commands don't define a 'result', so there's no need
to copy it back to userspace.

Remove the ability of the ioctl to submit commands to a different
namespace; it's just asking for trouble, and the use case I have in mind
will be addressed througha  different ioctl in the future.  That removes
the need for both the block_shift and nsid arguments.

Check that the opcode is one of 'read' or 'write'.  Future opcodes may
be added in the future, but we will need a different structure definition
for them.

The nblocks field is redefined to be 0-based.  This allows the user to
request the full 65536 blocks.

Don't byteswap the reftag, apptag and appmask.  Martin Petersen tells
me these are calculated in big-endian and are transmitted to the device
in big-endian.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

NVME_IOCTL_SUBMIT_IO has a struct nvme_user_io, not a struct nvme_rw_command
as a parameter, and NVME_IOCTL_DOWNLOAD_FW is a Write, not a Read.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Make ioctls work for 32-bit applications on 64-bit kernels.  The structures
are defined to be the same for both 32- and 64-bit applications, so
we can use the same handler for both.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Fill in all the num_possible_cpus() entries with duplicate pointers.
This reduces the complexity of the frequently-called get_nvmeq(), as
well as avoiding a bug in it when there are fewer queues than CPUs.
Reported-by: Shane Michael Matthews <shane.matthews@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Once there are no more bios on the congestion list, we can stop waking
up the nvme kthread every time a completion happens.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

If the last element in the PRP list fits on the end of the page, there's
no need to allocate an extra page to put that single element in.  It can
fit on the end of the page.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

The spec says this is a 0s based value.  We don't need to handle the
maximal value because it's reserved to mean "every namespace".
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

The head can never overrun the tail since we won't allocate enough command
IDs to let that happen.  The status codes are in sync with the spec.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Signed-off-by: Krzysztof Wierzbicki <krzysztof.wierzbicki@intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

The spec says we're not allowed to completely fill the submission queue.
Solve this by reducing the number of allocatable cmdids by 1.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

When we submit subsequent portions of the I/O, we need to access the
updated block, not start reading again from the original position.
This was showing up as miscompares in the XFS randholes testcase.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

NVMe scatterlists must be virtually contiguous, like almost all I/Os.
However, when the filesystem lays out files with a hole, it can be that
adjacent LBAs map to non-adjacent virtual addresses.  Handle this by
submitting one NVMe command at a time for each virtually discontiguous
range.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Linux implements Flush as a bit in the bio.  That means there may also be
data associated with the flush; if so the flush should be sent before the
data.  To avoid completing the bio twice, I add CMD_CTX_FLUSH to indicate
the completion routine should do nothing.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

The value written to the doorbell needs to be the first free index in
the queue, not the most recently used index in the queue.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

If interrupts are misconfigured, the kthread will be needed to process
admin queue completions.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

I got confused about whether this included the admin queue or not, and
had to resort to reading the spec.  It doesn't include the admin queue,
so make that clear in the name.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

This was the data transfer bit until spec rev 0.92
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Instead of trying to resubmit I/Os in the I/O completion path (in
interrupt context), wake up a kthread which will resubmit I/O from
user context.  This allows mke2fs to run to completion.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Return -EBUSY if the queue is full or -ENOMEM if we failed to allocate
memory (or map a scatterlist).  Also use GFP_ATOMIC to allocate the
nvme_bio and move the locking to the callers of nvme_submit_bio_queue().

In nvme_make_request(), don't permit an I/O to jump the queue -- if the
congestion list already has an entry, just add to the tail, rather than
trying to submit.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Add two reserved registers in the middle of the BAR to match the 1.0
spec plus ECN 0002.

Also rename IMC and ISC to INTMC and INTSC to conform with the spec.
We still don't need to use them :-)
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

In order to not overrun the sg array, we have to merge physically
contiguous pages into a single sg entry.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

If dma_map_sg returns 0 (failure), we need to fail the I/O.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

We were passing the nvme_queue to access the q_dmadev for the
dma_alloc_coherent calls, but since we moved to the dma pool API,
we really only need the nvme_dev.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Add a second memory pool for smaller I/Os.  We can pack 16 of these on a
single page instead of using an entire page for each one.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Calling dma_free_coherent from interrupt context causes warnings.
Using the DMA pools delays freeing until pool destruction, so avoids
the problem.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

There are too many things called 'info' in this driver.  This data
structure is auxiliary information for a struct bio, so call it nvme_bio,
or nbio when used as a variable.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

Add a pointer to the nvme_req_info to hold a new data structure
(nvme_prps) which contains a list of the pages allocated to this
particular request for holding PRP list entries.  nvme_setup_prps()
now returns this pointer.

To allocate and free the memory used for PRP lists, we need a struct
device, so we need to pass the nvme_queue pointer to many functions
which didn't use to need it.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

For multipage BIOs, we were always using sg[0] instead of advancing
through the list.  Oops :-)
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

If POISON_POINTER_DELTA isn't defined, ensure they're in page 0 which
should never be mapped.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

In the bio completion handler, check for bios on the congestion list
for this NVM queue.  Also, lock the congestion list in the make_request
function as the queue may end up being shared between multiple CPUs.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>