Releasing a zone write lock only when the write commnand that acquired
the lock completes can cause deadlocks due to potential command
reordering if the lock owning request is requeued and not executed. This
problem exists only with the scsi-mq path as, unlike the legacy path,
requests are moved out of the dispatch queue before being prepared and
so before locking a zone for a write command.
Since sd_uninit_cmnd() is now always called when a request is requeued,
call sd_zbc_write_unlock_zone() from that function for write requests
that acquired a zone lock instead of from sd_done(). Acquisition of a zone
lock by a write command is indicated using the new command
flag SCMD_ZONE_WRITE_LOCK.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Resetting a zone write pointer is equivalent to discarding sectors:
after a reset, the zone sectors will contain zeros (or the format
pattern). So there is no need for mutual exclusion between a zone reset
and write. Similarly to discard, make it the responsability of the user
to properly synchronize between reset and write (as is done now for
discard and write).
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
A value is assigned to the variable 'capacity' in sd_zbc_read_zones()
but that value is never used. Hence remove the variable 'capacity'.
[Damien: There is no need to initialize to 0 the variable 'ret'
in sd_zbc_read_zones()]
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Rename sd_zbc_setup_write_cmnd() to sd_zbc_write_lock_zone() to be clear
about what the function actually does. To be consistent, also rename
sd_zbc_cancel_write_cmnd() to sd_zbc_write_unlock_zone().
No functional change is introduced by this patch.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Normally, sd_read_capacity sets sdp->use_16_for_rw to 1 based on the
disk capacity so that READ16/WRITE16 are used for large drives.
However, for a zoned disk with RC_BASIS set to 0, the capacity reported
through READ_CAPACITY may be very small, leading to use_16_for_rw not being
set and READ10/WRITE10 commands being used, even after the actual zoned disk
capacity is corrected in sd_zbc_read_zones. This causes LBA offset overflow for
accesses beyond 2TB.
As the ZBC standard makes it mandatory for ZBC drives to support
the READ16/WRITE16 commands anyway, make sure that use_16_for_rw is set.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
eviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.
This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests. It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If sd_zbc_report_zones fails, the check for 'zone_blocks == 0'
later in the function accesses uninitialized data:
drivers/scsi/sd_zbc.c: In function ‘sd_zbc_read_zones’:
drivers/scsi/sd_zbc.c:520:7: error: ‘zone_blocks’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
This sets it to zero, which has the desired effect of leaving
the sd_zbc_read_zones successfully with sdkp->zone_blocks = 0.
Fixes: 89d9475610 ("sd: Implement support for ZBC devices")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Implement ZBC support functions to setup zoned disks, both
host-managed and host-aware models. Only zoned disks that satisfy
the following conditions are supported:
1) All zones are the same size, with the exception of an eventual
last smaller runt zone.
2) For host-managed disks, reads are unrestricted (reads are not
failed due to zone or write pointer alignement constraints).
Zoned disks that do not satisfy these 2 conditions are setup with
a capacity of 0 to prevent their use.
The function sd_zbc_read_zones, called from sd_revalidate_disk,
checks that the device satisfies the above two constraints. This
function may also change the disk capacity previously set by
sd_read_capacity for devices reporting only the capacity of
conventional zones at the beginning of the LBA range (i.e. devices
reporting rc_basis set to 0).
The capacity message output was moved out of sd_read_capacity into
a new function sd_print_capacity to include this eventual capacity
change by sd_zbc_read_zones. This new function also includes a call
to sd_zbc_print_zones to display the number of zones and zone size
of the device.
Signed-off-by: Hannes Reinecke <hare@suse.de>
[Damien: * Removed zone cache support
* Removed mapping of discard to reset write pointer command
* Modified sd_zbc_read_zones to include checks that the
device satisfies the kernel constraints
* Implemeted REPORT ZONES setup and post-processing based
on code from Shaun Tancheff <shaun.tancheff@seagate.com>
* Removed confusing use of 512B sector units in functions
interface]
Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Damien Le Moal