[PATCH v11 06/16] scsi: sd: Sort commands by LBA before resubmitting
From: Bart Van Assche <bvanassche@acm.org>
Date: 2023-08-22 19:19:04
Also in:
linux-scsi
Subsystem:
scsi subsystem, the rest · Maintainers:
"James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
Sort SCSI commands by LBA before the SCSI error handler resubmits these commands. This is necessary when resubmitting zoned writes (REQ_OP_WRITE) if multiple writes have been queued for a single zone. Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Damien Le Moal <dlemoal@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <redacted> Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- drivers/scsi/sd.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 3c668cfb146d..d4feac5de17a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c@@ -47,6 +47,7 @@ #include <linux/blkpg.h> #include <linux/blk-pm.h> #include <linux/delay.h> +#include <linux/list_sort.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/string_helpers.h>
@@ -117,6 +118,8 @@ static void sd_uninit_command(struct scsi_cmnd *SCpnt); static int sd_done(struct scsi_cmnd *); static void sd_eh_reset(struct scsi_cmnd *); static int sd_eh_action(struct scsi_cmnd *, int); +static bool sd_needs_prepare_resubmit(struct scsi_cmnd *cmd); +static void sd_prepare_resubmit(struct list_head *cmd_list); static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer); static void scsi_disk_release(struct device *cdev);
@@ -617,6 +620,8 @@ static struct scsi_driver sd_template = { .done = sd_done, .eh_action = sd_eh_action, .eh_reset = sd_eh_reset, + .eh_needs_prepare_resubmit = sd_needs_prepare_resubmit, + .eh_prepare_resubmit = sd_prepare_resubmit, }; /*
@@ -2018,6 +2023,46 @@ static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp) return eh_disp; } +static bool sd_needs_prepare_resubmit(struct scsi_cmnd *cmd) +{ + struct request *rq = scsi_cmd_to_rq(cmd); + + return !rq->q->limits.use_zone_write_lock && + blk_rq_is_seq_zoned_write(rq); +} + +static int sd_cmp_sector(void *priv, const struct list_head *_a, + const struct list_head *_b) +{ + struct scsi_cmnd *a = list_entry(_a, typeof(*a), eh_entry); + struct scsi_cmnd *b = list_entry(_b, typeof(*b), eh_entry); + struct request *rq_a = scsi_cmd_to_rq(a); + struct request *rq_b = scsi_cmd_to_rq(b); + bool use_zwl_a = rq_a->q->limits.use_zone_write_lock; + bool use_zwl_b = rq_b->q->limits.use_zone_write_lock; + + /* + * Order the commands that need zone write locking after the commands + * that do not need zone write locking. Order the commands that do not + * need zone write locking by LBA. Do not reorder the commands that + * need zone write locking. See also the comment above the list_sort() + * definition. + */ + if (use_zwl_a || use_zwl_b) + return use_zwl_a > use_zwl_b; + return blk_rq_pos(rq_a) > blk_rq_pos(rq_b); +} + +static void sd_prepare_resubmit(struct list_head *cmd_list) +{ + /* + * Sort pending SCSI commands in starting sector order. This is + * important if one of the SCSI devices associated with @shost is a + * zoned block device for which zone write locking is disabled. + */ + list_sort(NULL, cmd_list, sd_cmp_sector); +} + static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd) { struct request *req = scsi_cmd_to_rq(scmd);