tree 4eb9124ae72e1a905094c259465718793698e603
parent f03a567054fea4f9d43c50ec91338266c0bd588d
author James Bottomley <James.Bottomley@steeleye.com> 1123296340 -0500
committer James Bottomley <jejb@mulgrave.(none)> 1123512939 -0500

[SCSI] add global timeout to the scsi mid-layer

There are certain rogue devices (and the aic7xxx driver) that return
BUSY or QUEUE_FULL forever.  This code will apply a global timeout (of
the total number of retries times the per command timer) to a given
command.  If it is exceeded, the command is completed regardless of its
state.

The patch also removes the unused field in the command: timeout and
timeout_total.

This solves the problem of detecting an endless loop in the mid-layer
because of BUSY/QUEUE_FULL bouncing, but will not recover the device.
In the aic7xxx case, the driver can be recovered by sending a bus reset,
so possibly this should be tied into the error handler?

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>