Commit e013e13b authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds

libata: fix bug with non-ncq devices

The recent commit 2fca5ccf ("libata:
switch to using block layer tagging support") to enable support for
block layer tagging in libata was broken for non-NCQ devices

The block layer initializes the tag field to -1 to detect invalid uses
of a tag, and if the libata devices does NOT support NCQ, we just used
that field to index the internal command list.  So we need to check for
-1 first and only use the tag field if it's valid.
Signed-off-by: default avatarJens Axboe <>
Reported-by: default avatarAlexander Beregalov <>
Tested-by: default avatarPaul Mundt <>
Tested-by: default avatarDave Young <>
Tested-by: default avatarRafael J. Wysocki <>
Signed-off-by: default avatarLinus Torvalds <>
parent 57f8f7b6
......@@ -708,7 +708,11 @@ static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
struct ata_queued_cmd *qc;
if (cmd->request->tag != -1)
qc = ata_qc_new_init(dev, cmd->request->tag);
qc = ata_qc_new_init(dev, 0);
if (qc) {
qc->scsicmd = cmd;
qc->scsidone = done;
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