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authorTejun Heo <tj@kernel.org>2008-11-10 00:48:21 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-10 11:04:47 -0500
commit8a8bc22332ee6ea49137508467a76aa7f4367719 (patch)
treef41c62dc99c4249d592935b4659569081d4a190a /include/linux/libata.h
parentf7160c7573615ec82c691e294cf80d920b5d588d (diff)
libata: revert convert-to-block-tagging patches
This patch reverts the following three commits which convert libata to use block layer tagging. 43a49cbdf31e812c0d8f553d433b09b421f5d52c e013e13bf605b9e6b702adffbe2853cfc60e7806 2fca5ccf97d2c28bcfce44f5b07d85e74e3cd18e Although using block layer tagging is the right direction, due to the tight coupling among tag number, data structure allocation and hardware command slot allocation, libata doesn't work correctly with the current conversion. The biggest problem is guaranteeing that tag 0 is always used for non-NCQ commands. Due to the way blk-tag is implemented and how SCSI starts and finishes requests, such guarantee can't be made. I'm not sure whether this would actually break any low level driver but it doesn't look like a good idea to break such assumption given the frailty of ATA controllers. So, for the time being, keep using the old dumb in-libata qc allocation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axobe <jens.axboe@oracle.com> Cc: Jeff Garzik <jeff@garzik.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/libata.h')
-rw-r--r--include/linux/libata.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/libata.h b/include/linux/libata.h
index c7665a4134c5..59b0f1c807b5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -698,6 +698,7 @@ struct ata_port {
698 unsigned int cbl; /* cable type; ATA_CBL_xxx */ 698 unsigned int cbl; /* cable type; ATA_CBL_xxx */
699 699
700 struct ata_queued_cmd qcmd[ATA_MAX_QUEUE]; 700 struct ata_queued_cmd qcmd[ATA_MAX_QUEUE];
701 unsigned long qc_allocated;
701 unsigned int qc_active; 702 unsigned int qc_active;
702 int nr_active_links; /* #links with active qcs */ 703 int nr_active_links; /* #links with active qcs */
703 704