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Revert "libata: switch to dynamic allocation instead of ata_scsi_rbuf"
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This reverts commit a234f73.

The commit tried to get rid of the shared global SCSI response buffer.
Unfortunately, it added blocking allocation to atomic path.  Revert it
for now.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
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Tejun Heo committed Jan 18, 2017
1 parent d7969f5 commit d4ae1e2
Showing 1 changed file with 86 additions and 36 deletions.
122 changes: 86 additions & 36 deletions drivers/ata/libata-scsi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,9 @@

#define ATA_SCSI_RBUF_SIZE 4096

static DEFINE_SPINLOCK(ata_scsi_rbuf_lock);
static u8 ata_scsi_rbuf[ATA_SCSI_RBUF_SIZE];

typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc);

static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
Expand Down Expand Up @@ -2053,6 +2056,53 @@ struct ata_scsi_args {
struct scsi_cmnd *cmd;
};

/**
* ata_scsi_rbuf_get - Map response buffer.
* @cmd: SCSI command containing buffer to be mapped.
* @flags: unsigned long variable to store irq enable status
* @copy_in: copy in from user buffer
*
* Prepare buffer for simulated SCSI commands.
*
* LOCKING:
* spin_lock_irqsave(ata_scsi_rbuf_lock) on success
*
* RETURNS:
* Pointer to response buffer.
*/
static void *ata_scsi_rbuf_get(struct scsi_cmnd *cmd, bool copy_in,
unsigned long *flags)
{
spin_lock_irqsave(&ata_scsi_rbuf_lock, *flags);

memset(ata_scsi_rbuf, 0, ATA_SCSI_RBUF_SIZE);
if (copy_in)
sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
return ata_scsi_rbuf;
}

/**
* ata_scsi_rbuf_put - Unmap response buffer.
* @cmd: SCSI command containing buffer to be unmapped.
* @copy_out: copy out result
* @flags: @flags passed to ata_scsi_rbuf_get()
*
* Returns rbuf buffer. The result is copied to @cmd's buffer if
* @copy_back is true.
*
* LOCKING:
* Unlocks ata_scsi_rbuf_lock.
*/
static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, bool copy_out,
unsigned long *flags)
{
if (copy_out)
sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
spin_unlock_irqrestore(&ata_scsi_rbuf_lock, *flags);
}

/**
* ata_scsi_rbuf_fill - wrapper for SCSI command simulators
* @args: device IDENTIFY data / SCSI command of interest.
Expand All @@ -2071,22 +2121,17 @@ struct ata_scsi_args {
static void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
unsigned int (*actor)(struct ata_scsi_args *args, u8 *rbuf))
{
u8 *rbuf;
unsigned int rc;
struct scsi_cmnd *cmd = args->cmd;
u8 *buf;
unsigned long flags;

buf = kzalloc(ATA_SCSI_RBUF_SIZE, GFP_NOIO);
if (!buf) {
ata_scsi_set_sense(args->dev, cmd, NOT_READY, 0x08, 0);
return;
}
rbuf = ata_scsi_rbuf_get(cmd, false, &flags);
rc = actor(args, rbuf);
ata_scsi_rbuf_put(cmd, rc == 0, &flags);

if (actor(args, buf) == 0) {
sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
buf, ATA_SCSI_RBUF_SIZE);
if (rc == 0)
cmd->result = SAM_STAT_GOOD;
}

kfree(buf);
}

/**
Expand Down Expand Up @@ -3318,17 +3363,24 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
*
* Return: Number of bytes copied into sglist.
*/
static ssize_t ata_format_dsm_trim_descr(struct scsi_cmnd *cmd, u32 trmax,
static size_t ata_format_dsm_trim_descr(struct scsi_cmnd *cmd, u32 trmax,
u64 sector, u32 count)
{
struct scsi_device *sdp = cmd->device;
size_t len = sdp->sector_size;
size_t r;
__le64 *buf;
u32 i = 0;
unsigned long flags;

buf = kzalloc(cmd->device->sector_size, GFP_NOFS);
if (!buf)
return -ENOMEM;
WARN_ON(len > ATA_SCSI_RBUF_SIZE);

if (len > ATA_SCSI_RBUF_SIZE)
len = ATA_SCSI_RBUF_SIZE;

spin_lock_irqsave(&ata_scsi_rbuf_lock, flags);
buf = ((void *)ata_scsi_rbuf);
memset(buf, 0, len);
while (i < trmax) {
u64 entry = sector |
((u64)(count > 0xffff ? 0xffff : count) << 48);
Expand All @@ -3338,9 +3390,9 @@ static ssize_t ata_format_dsm_trim_descr(struct scsi_cmnd *cmd, u32 trmax,
count -= 0xffff;
sector += 0xffff;
}
r = sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf,
cmd->device->sector_size);
kfree(buf);
r = sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf, len);
spin_unlock_irqrestore(&ata_scsi_rbuf_lock, flags);

return r;
}

Expand All @@ -3356,25 +3408,31 @@ static ssize_t ata_format_dsm_trim_descr(struct scsi_cmnd *cmd, u32 trmax,
*
* Return: Number of bytes copied into sglist.
*/
static ssize_t ata_format_sct_write_same(struct scsi_cmnd *cmd, u64 lba,
u64 num)
static size_t ata_format_sct_write_same(struct scsi_cmnd *cmd, u64 lba, u64 num)
{
struct scsi_device *sdp = cmd->device;
size_t len = sdp->sector_size;
size_t r;
u16 *buf;
unsigned long flags;

buf = kzalloc(cmd->device->sector_size, GFP_NOIO);
if (!buf)
return -ENOMEM;
spin_lock_irqsave(&ata_scsi_rbuf_lock, flags);
buf = ((void *)ata_scsi_rbuf);

put_unaligned_le16(0x0002, &buf[0]); /* SCT_ACT_WRITE_SAME */
put_unaligned_le16(0x0101, &buf[1]); /* WRITE PTRN FG */
put_unaligned_le64(lba, &buf[2]);
put_unaligned_le64(num, &buf[6]);
put_unaligned_le32(0u, &buf[10]); /* pattern */

r = sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf,
cmd->device->sector_size);
kfree(buf);
WARN_ON(len > ATA_SCSI_RBUF_SIZE);

if (len > ATA_SCSI_RBUF_SIZE)
len = ATA_SCSI_RBUF_SIZE;

r = sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf, len);
spin_unlock_irqrestore(&ata_scsi_rbuf_lock, flags);

return r;
}

Expand All @@ -3399,7 +3457,7 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc)
u64 block;
u32 n_block;
const u32 trmax = len >> 3;
ssize_t size;
u32 size;
u16 fp;
u8 bp = 0xff;
u8 unmap = cdb[1] & 0x8;
Expand Down Expand Up @@ -3450,8 +3508,6 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc)
*/
if (unmap) {
size = ata_format_dsm_trim_descr(scmd, trmax, block, n_block);
if (size < 0)
goto comm_fail;
if (size != len)
goto invalid_param_len;

Expand All @@ -3475,8 +3531,6 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc)
}
} else {
size = ata_format_sct_write_same(scmd, block, n_block);
if (size < 0)
goto comm_fail;
if (size != len)
goto invalid_param_len;

Expand Down Expand Up @@ -3515,10 +3569,6 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc)
/* "Invalid command operation code" */
ata_scsi_set_sense(dev, scmd, ILLEGAL_REQUEST, 0x20, 0x0);
return 1;
comm_fail:
/* "Logical unit communication failure" */
ata_scsi_set_sense(dev, scmd, NOT_READY, 0x08, 0);
return 1;
}

/**
Expand Down

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