A build warning was triggered due to excessive stack usage in sd_revalidate_disk():

drivers/scsi/sd.c: In function ‘sd_revalidate_disk.isra’: drivers/scsi/sd.c:3824:1: warning: the frame size of 1160 bytes is larger than 1024 bytes [-Wframe-larger-than=]

This is caused by a large local struct queue_limits (~400B) allocated on the stack. Replacing it with a heap allocation using kmalloc() significantly reduces frame usage. Kernel stack is limited (~8 KB), and allocating large structs on the stack is discouraged. As the function already performs heap allocations (e.g. for buffer), this change fits well.

Fixes: 804e498e0496 ("sd: convert to the atomic queue limits API") Cc: stable@vger.kernel.org Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Abinash Singh abinashsinghlalotra@gmail.com

--- drivers/scsi/sd.c | 50 ++++++++++++++++++++++++++--------------------- 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 5b8668accf8e..bf12e23f1212 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3696,10 +3696,10 @@ static int sd_revalidate_disk(struct gendisk *disk) struct scsi_disk *sdkp = scsi_disk(disk); struct scsi_device *sdp = sdkp->device; sector_t old_capacity = sdkp->capacity; - struct queue_limits lim; - unsigned char *buffer; + struct queue_limits *lim = NULL; + unsigned char *buffer = NULL; unsigned int dev_max; - int err; + int err = 0;

SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_revalidate_disk\n")); @@ -3711,6 +3711,10 @@ static int sd_revalidate_disk(struct gendisk *disk) if (!scsi_device_online(sdp)) goto out;

+ lim = kmalloc(sizeof(*lim), GFP_KERNEL); + if (!lim) + goto out; + buffer = kmalloc(SD_BUF_SIZE, GFP_KERNEL); if (!buffer) { sd_printk(KERN_WARNING, sdkp, "sd_revalidate_disk: Memory " @@ -3720,14 +3724,14 @@ static int sd_revalidate_disk(struct gendisk *disk)

sd_spinup_disk(sdkp);

- lim = queue_limits_start_update(sdkp->disk->queue); + *lim = queue_limits_start_update(sdkp->disk->queue);

/* * Without media there is no reason to ask; moreover, some devices * react badly if we do. */ if (sdkp->media_present) { - sd_read_capacity(sdkp, &lim, buffer); + sd_read_capacity(sdkp, lim, buffer); /* * Some USB/UAS devices return generic values for mode pages * until the media has been accessed. Trigger a READ operation @@ -3741,17 +3745,17 @@ static int sd_revalidate_disk(struct gendisk *disk) * cause this to be updated correctly and any device which * doesn't support it should be treated as rotational. */ - lim.features |= (BLK_FEAT_ROTATIONAL | BLK_FEAT_ADD_RANDOM); + lim->features |= (BLK_FEAT_ROTATIONAL | BLK_FEAT_ADD_RANDOM);

if (scsi_device_supports_vpd(sdp)) { sd_read_block_provisioning(sdkp); - sd_read_block_limits(sdkp, &lim); + sd_read_block_limits(sdkp, lim); sd_read_block_limits_ext(sdkp); - sd_read_block_characteristics(sdkp, &lim); - sd_zbc_read_zones(sdkp, &lim, buffer); + sd_read_block_characteristics(sdkp, lim); + sd_zbc_read_zones(sdkp, lim, buffer); }

- sd_config_discard(sdkp, &lim, sd_discard_mode(sdkp)); + sd_config_discard(sdkp, lim, sd_discard_mode(sdkp));

sd_print_capacity(sdkp, old_capacity);

@@ -3761,47 +3765,46 @@ static int sd_revalidate_disk(struct gendisk *disk) sd_read_app_tag_own(sdkp, buffer); sd_read_write_same(sdkp, buffer); sd_read_security(sdkp, buffer); - sd_config_protection(sdkp, &lim); + sd_config_protection(sdkp, lim); }

/* * We now have all cache related info, determine how we deal * with flush requests. */ - sd_set_flush_flag(sdkp, &lim); + sd_set_flush_flag(sdkp, lim);

/* Initial block count limit based on CDB TRANSFER LENGTH field size. */ dev_max = sdp->use_16_for_rw ? SD_MAX_XFER_BLOCKS : SD_DEF_XFER_BLOCKS;

/* Some devices report a maximum block count for READ/WRITE requests. */ dev_max = min_not_zero(dev_max, sdkp->max_xfer_blocks); - lim.max_dev_sectors = logical_to_sectors(sdp, dev_max); + lim->max_dev_sectors = logical_to_sectors(sdp, dev_max);

if (sd_validate_min_xfer_size(sdkp)) - lim.io_min = logical_to_bytes(sdp, sdkp->min_xfer_blocks); + lim->io_min = logical_to_bytes(sdp, sdkp->min_xfer_blocks); else - lim.io_min = 0; + lim->io_min = 0;

/* * Limit default to SCSI host optimal sector limit if set. There may be * an impact on performance for when the size of a request exceeds this * host limit. */ - lim.io_opt = sdp->host->opt_sectors << SECTOR_SHIFT; + lim->io_opt = sdp->host->opt_sectors << SECTOR_SHIFT; if (sd_validate_opt_xfer_size(sdkp, dev_max)) { - lim.io_opt = min_not_zero(lim.io_opt, + lim->io_opt = min_not_zero(lim->io_opt, logical_to_bytes(sdp, sdkp->opt_xfer_blocks)); }

sdkp->first_scan = 0;

set_capacity_and_notify(disk, logical_to_sectors(sdp, sdkp->capacity)); - sd_config_write_same(sdkp, &lim); - kfree(buffer); + sd_config_write_same(sdkp, lim);

- err = queue_limits_commit_update_frozen(sdkp->disk->queue, &lim); + err = queue_limits_commit_update_frozen(sdkp->disk->queue, lim); if (err) - return err; + goto out;

/* * Query concurrent positioning ranges after @@ -3820,7 +3823,10 @@ static int sd_revalidate_disk(struct gendisk *disk) set_capacity_and_notify(disk, 0);

out: - return 0; + kfree(buffer); + kfree(lim); + + return err; }

/**