Commit 4f777ed2 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by James Bottomley
Browse files

[SCSI] kill scsi_assign_lock 



scsi_assign_lock has been unused for a long time and is a bad idea
in general, so kill it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 3b003157

Documentation/scsi/scsi_mid_low_api.txt

+5 −26
Original line number Diff line number Diff line
@@ -375,7 +375,6 @@ Summary: 
   scsi_add_device - creates new scsi device (lu) instance

   scsi_add_host - perform sysfs registration and set up transport class

   scsi_adjust_queue_depth - change the queue depth on a SCSI device

   scsi_assign_lock - replace default host_lock with given lock

   scsi_bios_ptable - return copy of block device's partition table

   scsi_block_requests - prevent further commands being queued to given host

   scsi_deactivate_tcq - turn off tag command queueing
@@ -488,20 +487,6 @@ void scsi_adjust_queue_depth(struct scsi_device * sdev, int tagged, 
                             int tags)





/**

 * scsi_assign_lock - replace default host_lock with given lock

 * @shost: a pointer to a scsi host instance

 * @lock: pointer to lock to replace host_lock for this host

 *

 *      Returns nothing

 *

 *      Might block: no

 *

 *      Defined in: include/scsi/scsi_host.h .

 **/

void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)





/**

 * scsi_bios_ptable - return copy of block device's partition table

 * @dev:        pointer to block device
@@ -1366,17 +1351,11 @@ Locks 
Each struct Scsi_Host instance has a spin_lock called struct 

Scsi_Host::default_lock which is initialized in scsi_host_alloc() [found in 

hosts.c]. Within the same function the struct Scsi_Host::host_lock pointer

is initialized to point at default_lock with the scsi_assign_lock() function.

Thereafter lock and unlock operations performed by the mid level use the

struct Scsi_Host::host_lock pointer.



LLDs can override the use of struct Scsi_Host::default_lock by

using scsi_assign_lock(). The earliest opportunity to do this would

be in the detect() function after it has invoked scsi_register(). It

could be replaced by a coarser grain lock (e.g. per driver) or a

lock of equal granularity (i.e. per host). Using finer grain locks 

(e.g. per SCSI device) may be possible by juggling locks in

queuecommand().

is initialized to point at default_lock.  Thereafter lock and unlock

operations performed by the mid level use the struct Scsi_Host::host_lock

pointer.  Previously drivers could override the host_lock pointer but

this is not allowed anymore.





Autosense

=========

drivers/scsi/hosts.c

+2 −2
Original line number Diff line number Diff line
@@ -301,8 +301,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 
	if (!shost)

		return NULL;



	spin_lock_init(&shost->default_lock);

	scsi_assign_lock(shost, &shost->default_lock);

	shost->host_lock = &shost->default_lock;

	spin_lock_init(shost->host_lock);

	shost->shost_state = SHOST_CREATED;

	INIT_LIST_HEAD(&shost->__devices);

	INIT_LIST_HEAD(&shost->__targets);

include/scsi/scsi_host.h

+0 −5
Original line number Diff line number Diff line
@@ -651,11 +651,6 @@ extern const char *scsi_host_state_name(enum scsi_host_state); 


extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);



static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)

{

	shost->host_lock = lock;

}



static inline struct device *scsi_get_device(struct Scsi_Host *shost)

{

        return shost->shost_gendev.parent;