static int sg_add(struct device *, struct class_interface *);
static void sg_remove(struct device *, struct class_interface *);
-static DEFINE_SPINLOCK(sg_open_exclusive_lock);
-
static DEFINE_IDR(sg_index_idr);
-static DEFINE_RWLOCK(sg_index_lock); /* Also used to lock
- file descriptor list for device */
+static DEFINE_RWLOCK(sg_index_lock);
static struct class_interface sg_interface = {
.add_dev = sg_add,
} Sg_request;
typedef struct sg_fd { /* holds the state of a file descriptor */
- /* sfd_siblings is protected by sg_index_lock */
- struct list_head sfd_siblings;
+ struct list_head sfd_siblings; /* protected by sfd_lock of device */
struct sg_device *parentdp; /* owning device */
wait_queue_head_t read_wait; /* queue read until command done */
rwlock_t rq_list_lock; /* protect access to list in req_arr */
typedef struct sg_device { /* holds the state of each scsi generic device */
struct scsi_device *device;
- wait_queue_head_t o_excl_wait; /* queue open() when O_EXCL in use */
int sg_tablesize; /* adapter's max scatter-gather table size */
u32 index; /* device index number */
- /* sfds is protected by sg_index_lock */
+ spinlock_t sfd_lock; /* protect file descriptor list for device */
struct list_head sfds;
+ struct rw_semaphore o_sem; /* exclude open should hold this rwsem */
volatile char detached; /* 0->attached, 1->detached pending removal */
- /* exclude protected by sg_open_exclusive_lock */
char exclude; /* opened for exclusive access */
char sgdebug; /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
struct gendisk *disk;
return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
}
-static int get_exclude(Sg_device *sdp)
-{
- unsigned long flags;
- int ret;
-
- spin_lock_irqsave(&sg_open_exclusive_lock, flags);
- ret = sdp->exclude;
- spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
- return ret;
-}
-
-static int set_exclude(Sg_device *sdp, char val)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&sg_open_exclusive_lock, flags);
- sdp->exclude = val;
- spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
- return val;
-}
-
static int sfds_list_empty(Sg_device *sdp)
{
unsigned long flags;
int ret;
- read_lock_irqsave(&sg_index_lock, flags);
+ spin_lock_irqsave(&sdp->sfd_lock, flags);
ret = list_empty(&sdp->sfds);
- read_unlock_irqrestore(&sg_index_lock, flags);
+ spin_unlock_irqrestore(&sdp->sfd_lock, flags);
return ret;
}
struct request_queue *q;
Sg_device *sdp;
Sg_fd *sfp;
- int res;
int retval;
nonseekable_open(inode, filp);
goto error_out;
}
- if (flags & O_EXCL) {
- if (O_RDONLY == (flags & O_ACCMODE)) {
- retval = -EPERM; /* Can't lock it with read only access */
- goto error_out;
- }
- if (!sfds_list_empty(sdp) && (flags & O_NONBLOCK)) {
- retval = -EBUSY;
- goto error_out;
- }
- res = wait_event_interruptible(sdp->o_excl_wait,
- ((!sfds_list_empty(sdp) || get_exclude(sdp)) ? 0 : set_exclude(sdp, 1)));
- if (res) {
- retval = res; /* -ERESTARTSYS because signal hit process */
- goto error_out;
- }
- } else if (get_exclude(sdp)) { /* some other fd has an exclusive lock on dev */
- if (flags & O_NONBLOCK) {
- retval = -EBUSY;
- goto error_out;
- }
- res = wait_event_interruptible(sdp->o_excl_wait, !get_exclude(sdp));
- if (res) {
- retval = res; /* -ERESTARTSYS because signal hit process */
- goto error_out;
- }
- }
- if (sdp->detached) {
- retval = -ENODEV;
+ if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE))) {
+ retval = -EPERM; /* Can't lock it with read only access */
goto error_out;
}
+ if (flags & O_NONBLOCK) {
+ if (flags & O_EXCL) {
+ if (!down_write_trylock(&sdp->o_sem)) {
+ retval = -EBUSY;
+ goto error_out;
+ }
+ } else {
+ if (!down_read_trylock(&sdp->o_sem)) {
+ retval = -EBUSY;
+ goto error_out;
+ }
+ }
+ } else {
+ if (flags & O_EXCL)
+ down_write(&sdp->o_sem);
+ else
+ down_read(&sdp->o_sem);
+ }
+ /* Since write lock is held, no need to check sfd_list */
+ if (flags & O_EXCL)
+ sdp->exclude = 1; /* used by release lock */
+
if (sfds_list_empty(sdp)) { /* no existing opens on this device */
sdp->sgdebug = 0;
q = sdp->device->request_queue;
sdp->sg_tablesize = queue_max_segments(q);
}
- if ((sfp = sg_add_sfp(sdp, dev)))
+ sfp = sg_add_sfp(sdp, dev);
+ if (!IS_ERR(sfp))
filp->private_data = sfp;
+ /* retval is already provably zero at this point because of the
+ * check after retval = scsi_autopm_get_device(sdp->device))
+ */
else {
+ retval = PTR_ERR(sfp);
+
if (flags & O_EXCL) {
- set_exclude(sdp, 0); /* undo if error */
- wake_up_interruptible(&sdp->o_excl_wait);
- }
- retval = -ENOMEM;
- goto error_out;
- }
- retval = 0;
+ sdp->exclude = 0; /* undo if error */
+ up_write(&sdp->o_sem);
+ } else
+ up_read(&sdp->o_sem);
error_out:
- if (retval) {
scsi_autopm_put_device(sdp->device);
sdp_put:
scsi_device_put(sdp->device);
{
Sg_device *sdp;
Sg_fd *sfp;
+ int excl;
if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
- set_exclude(sdp, 0);
- wake_up_interruptible(&sdp->o_excl_wait);
+ excl = sdp->exclude;
+ sdp->exclude = 0;
+ if (excl)
+ up_write(&sdp->o_sem);
+ else
+ up_read(&sdp->o_sem);
scsi_autopm_put_device(sdp->device);
kref_put(&sfp->f_ref, sg_remove_sfp);
disk->first_minor = k;
sdp->disk = disk;
sdp->device = scsidp;
+ spin_lock_init(&sdp->sfd_lock);
INIT_LIST_HEAD(&sdp->sfds);
- init_waitqueue_head(&sdp->o_excl_wait);
+ init_rwsem(&sdp->o_sem);
sdp->sg_tablesize = queue_max_segments(q);
sdp->index = k;
kref_init(&sdp->d_ref);
/* Need a write lock to set sdp->detached. */
write_lock_irqsave(&sg_index_lock, iflags);
+ spin_lock(&sdp->sfd_lock);
sdp->detached = 1;
list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
wake_up_interruptible(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
}
+ spin_unlock(&sdp->sfd_lock);
write_unlock_irqrestore(&sg_index_lock, iflags);
sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
if (!sfp)
- return NULL;
+ return ERR_PTR(-ENOMEM);
init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);
sfp->cmd_q = SG_DEF_COMMAND_Q;
sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
sfp->parentdp = sdp;
- write_lock_irqsave(&sg_index_lock, iflags);
+ spin_lock_irqsave(&sdp->sfd_lock, iflags);
+ if (sdp->detached) {
+ spin_unlock_irqrestore(&sdp->sfd_lock, iflags);
+ return ERR_PTR(-ENODEV);
+ }
list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
- write_unlock_irqrestore(&sg_index_lock, iflags);
+ spin_unlock_irqrestore(&sdp->sfd_lock, iflags);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
if (unlikely(sg_big_buff != def_reserved_size))
sg_big_buff = def_reserved_size;
struct sg_device *sdp = sfp->parentdp;
unsigned long iflags;
- write_lock_irqsave(&sg_index_lock, iflags);
+ spin_lock_irqsave(&sdp->sfd_lock, iflags);
list_del(&sfp->sfd_siblings);
- write_unlock_irqrestore(&sg_index_lock, iflags);
- wake_up_interruptible(&sdp->o_excl_wait);
+ spin_unlock_irqrestore(&sdp->sfd_lock, iflags);
INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
schedule_work(&sfp->ew.work);
return 0;
}
-/* must be called while holding sg_index_lock */
+/* must be called while holding sg_index_lock and sfd_lock */
static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
{
int k, m, new_interface, blen, usg;
read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
- if (sdp && !list_empty(&sdp->sfds)) {
- struct scsi_device *scsidp = sdp->device;
+ if (sdp) {
+ spin_lock(&sdp->sfd_lock);
+ if (!list_empty(&sdp->sfds)) {
+ struct scsi_device *scsidp = sdp->device;
- seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
- if (sdp->detached)
- seq_printf(s, "detached pending close ");
- else
- seq_printf
- (s, "scsi%d chan=%d id=%d lun=%d em=%d",
- scsidp->host->host_no,
- scsidp->channel, scsidp->id,
- scsidp->lun,
- scsidp->host->hostt->emulated);
- seq_printf(s, " sg_tablesize=%d excl=%d\n",
- sdp->sg_tablesize, get_exclude(sdp));
- sg_proc_debug_helper(s, sdp);
+ seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
+ if (sdp->detached)
+ seq_printf(s, "detached pending close ");
+ else
+ seq_printf
+ (s, "scsi%d chan=%d id=%d lun=%d em=%d",
+ scsidp->host->host_no,
+ scsidp->channel, scsidp->id,
+ scsidp->lun,
+ scsidp->host->hostt->emulated);
+ seq_printf(s, " sg_tablesize=%d excl=%d\n",
+ sdp->sg_tablesize, sdp->exclude);
+ sg_proc_debug_helper(s, sdp);
+ }
+ spin_unlock(&sdp->sfd_lock);
}
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
projects / cascardo / linux.git / blobdiff