[PATCH 4/4] ata: libata-core: do not retry reading the log on timeout

[Niklas Cassel <niklas.cassel@wdc.com>]

ata_read_log_page() first tries to read the log using READ LOG DMA EXT.
If that fails it will instead try to read the log using READ LOG EXT.

ata_exec_internal_sg() is synchronous, so it will wait for the command to
finish. If we actually got an error back from the device, it is correct
to retry. However, if the command timed out, ata_exec_internal_sg() will
freeze the port.

There is no point in retrying if the port is frozen, as
ata_exec_internal_sg() will return AC_ERR_SYSTEM on a frozen port,
without ever sending the command down to the drive.

Therefore, avoid retrying if the first command froze the port, as that
will result in a misleading AC_ERR_SYSTEM error print, instead of printing
the error that actually caused the port to be frozen (AC_ERR_TIMEOUT).

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 1cf326dd7c41..6ae5787103e7 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2000,7 +2000,8 @@ unsigned int ata_read_log_page(struct ata_device *dev, u8 log,
 	if (err_mask) {
 		if (dma) {
 			dev->horkage |= ATA_HORKAGE_NO_DMA_LOG;
-			goto retry;
+			if (!ata_port_is_frozen(dev->link->ap))
+				goto retry;
 		}
 		ata_dev_err(dev,
 			    "Read log 0x%02x page 0x%02x failed, Emask 0x%x\n",
-- 
2.37.3