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libata: avoid global response buffer in atapi_qc_complete

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We only need to look at 4 bytes of the inquiry response for ATAPI
devices.  Instead of using the global ata_scsi_rbuf just use a
a stack buffer.  Also factor the fixup into it's own little helper
function to make it more readable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christoph Hellwig 2017-01-10 09:41:43 +01:00 committed by Tejun Heo
parent fb1b8b1175
commit aa18da8b7e
1 changed files with 22 additions and 24 deletions
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46
drivers/ata/libata-scsi.c
View file

@ -2873,6 +2873,26 @@ static void atapi_request_sense(struct ata_queued_cmd *qc)
DPRINTK("EXIT\n");
}
/*
* ATAPI devices typically report zero for their SCSI version, and sometimes
* deviate from the spec WRT response data format. If SCSI version is
* reported as zero like normal, then we make the following fixups:
* 1) Fake MMC-5 version, to indicate to the Linux scsi midlayer this is a
* modern device.
* 2) Ensure response data format / ATAPI information are always correct.
*/
static void atapi_fixup_inquiry(struct scsi_cmnd *cmd)
{
u8 buf[4];
sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf, 4);
if (buf[2] == 0) {
buf[2] = 0x5;
buf[3] = 0x32;
}
sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf, 4);
}
static void atapi_qc_complete(struct ata_queued_cmd *qc)
{
struct scsi_cmnd *cmd = qc->scsicmd;
@ -2927,30 +2947,8 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc)
*/
ata_gen_passthru_sense(qc);
} else {
u8 *scsicmd = cmd->cmnd;
if ((scsicmd[0] == INQUIRY) && ((scsicmd[1] & 0x03) == 0)) {
unsigned long flags;
u8 *buf;
buf = ata_scsi_rbuf_get(cmd, true, &flags);
/* ATAPI devices typically report zero for their SCSI version,
* and sometimes deviate from the spec WRT response data
* format. If SCSI version is reported as zero like normal,
* then we make the following fixups: 1) Fake MMC-5 version,
* to indicate to the Linux scsi midlayer this is a modern
* device. 2) Ensure response data format / ATAPI information
* are always correct.
*/
if (buf[2] == 0) {
buf[2] = 0x5;
buf[3] = 0x32;
}
ata_scsi_rbuf_put(cmd, true, &flags);
}
if (cmd->cmnd[0] == INQUIRY && (cmd->cmnd[1] & 0x03) == 0)
atapi_fixup_inquiry(cmd);
cmd->result = SAM_STAT_GOOD;
}