From 6c648d95a6af4a79241a916871df17c84c68ea20 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Sat, 18 Aug 2012 15:20:39 -0400 Subject: [PATCH] [SCSI] st: get rid of scsi_tapes array MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit st currently allocates an array to store pointers to all of the scsi_tape objects. It's used to discover available indexes to use as the base for the minor number selection and later to look up scsi_tape devices for character devices. We switch to using an IDR for minor selection and a pointer from st_modedef back to scsi_tape for the lookups. Reviewed-by: Lee Duncan Signed-off-by: Jeff Mahoney Acked-by: Kai Mäkisara Signed-off-by: James Bottomley --- drivers/scsi/st.c | 178 ++++++++++++++++++---------------------------- drivers/scsi/st.h | 2 + 2 files changed, 70 insertions(+), 110 deletions(-) diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 492b53b6e51d..052622fdba02 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -37,6 +37,7 @@ static const char *verstr = "20101219"; #include #include #include +#include #include #include @@ -81,9 +82,6 @@ static int try_direct_io = TRY_DIRECT_IO; static int try_rdio = 1; static int try_wdio = 1; -static int st_dev_max; -static int st_nr_dev; - static struct class st_sysfs_class; static struct device_attribute st_dev_attrs[]; @@ -174,13 +172,9 @@ static int debugging = DEBUG; 24 bits) */ #define SET_DENS_AND_BLK 0x10001 -static DEFINE_RWLOCK(st_dev_arr_lock); - static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE; static int st_max_sg_segs = ST_MAX_SG; -static struct scsi_tape **scsi_tapes = NULL; - static int modes_defined; static int enlarge_buffer(struct st_buffer *, int, int); @@ -222,6 +216,10 @@ static void scsi_tape_release(struct kref *); #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref) static DEFINE_MUTEX(st_ref_mutex); +static DEFINE_SPINLOCK(st_index_lock); +static DEFINE_SPINLOCK(st_use_lock); +static DEFINE_IDR(st_index_idr); + #include "osst_detect.h" @@ -239,10 +237,9 @@ static struct scsi_tape *scsi_tape_get(int dev) struct scsi_tape *STp = NULL; mutex_lock(&st_ref_mutex); - write_lock(&st_dev_arr_lock); + spin_lock(&st_index_lock); - if (dev < st_dev_max && scsi_tapes != NULL) - STp = scsi_tapes[dev]; + STp = idr_find(&st_index_idr, dev); if (!STp) goto out; kref_get(&STp->kref); @@ -259,7 +256,7 @@ out_put: kref_put(&STp->kref, scsi_tape_release); STp = NULL; out: - write_unlock(&st_dev_arr_lock); + spin_unlock(&st_index_lock); mutex_unlock(&st_ref_mutex); return STp; } @@ -1202,12 +1199,12 @@ static int st_open(struct inode *inode, struct file *filp) return -ENXIO; } - write_lock(&st_dev_arr_lock); filp->private_data = STp; name = tape_name(STp); + spin_lock(&st_use_lock); if (STp->in_use) { - write_unlock(&st_dev_arr_lock); + spin_unlock(&st_use_lock); scsi_tape_put(STp); mutex_unlock(&st_mutex); DEB( printk(ST_DEB_MSG "%s: Device already in use.\n", name); ) @@ -1215,7 +1212,7 @@ static int st_open(struct inode *inode, struct file *filp) } STp->in_use = 1; - write_unlock(&st_dev_arr_lock); + spin_unlock(&st_use_lock); STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0; if (scsi_autopm_get_device(STp->device) < 0) { @@ -1404,9 +1401,9 @@ static int st_release(struct inode *inode, struct file *filp) do_door_lock(STp, 0); normalize_buffer(STp->buffer); - write_lock(&st_dev_arr_lock); + spin_lock(&st_use_lock); STp->in_use = 0; - write_unlock(&st_dev_arr_lock); + spin_unlock(&st_use_lock); scsi_autopm_put_device(STp->device); scsi_tape_put(STp); @@ -4029,58 +4026,16 @@ static int st_probe(struct device *dev) goto out_buffer_free; } - write_lock(&st_dev_arr_lock); - if (st_nr_dev >= st_dev_max) { - struct scsi_tape **tmp_da; - int tmp_dev_max; - - tmp_dev_max = max(st_nr_dev * 2, 8); - if (tmp_dev_max > ST_MAX_TAPES) - tmp_dev_max = ST_MAX_TAPES; - if (tmp_dev_max <= st_nr_dev) { - write_unlock(&st_dev_arr_lock); - printk(KERN_ERR "st: Too many tape devices (max. %d).\n", - ST_MAX_TAPES); - goto out_put_disk; - } - - tmp_da = kzalloc(tmp_dev_max * sizeof(struct scsi_tape *), GFP_ATOMIC); - if (tmp_da == NULL) { - write_unlock(&st_dev_arr_lock); - printk(KERN_ERR "st: Can't extend device array.\n"); - goto out_put_disk; - } - - if (scsi_tapes != NULL) { - memcpy(tmp_da, scsi_tapes, - st_dev_max * sizeof(struct scsi_tape *)); - kfree(scsi_tapes); - } - scsi_tapes = tmp_da; - - st_dev_max = tmp_dev_max; - } - - for (i = 0; i < st_dev_max; i++) - if (scsi_tapes[i] == NULL) - break; - if (i >= st_dev_max) - panic("scsi_devices corrupt (st)"); - tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC); if (tpnt == NULL) { - write_unlock(&st_dev_arr_lock); printk(KERN_ERR "st: Can't allocate device descriptor.\n"); goto out_put_disk; } kref_init(&tpnt->kref); tpnt->disk = disk; - sprintf(disk->disk_name, "st%d", i); disk->private_data = &tpnt->driver; disk->queue = SDp->request_queue; tpnt->driver = &st_template; - scsi_tapes[i] = tpnt; - dev_num = i; tpnt->device = SDp; if (SDp->scsi_level <= 2) @@ -4126,6 +4081,7 @@ static int st_probe(struct device *dev) STm->default_compression = ST_DONT_TOUCH; STm->default_blksize = (-1); /* No forced size */ STm->default_density = (-1); /* No forced density */ + STm->tape = tpnt; } for (i = 0; i < ST_NBR_PARTITIONS; i++) { @@ -4145,8 +4101,29 @@ static int st_probe(struct device *dev) tpnt->blksize_changed = 0; mutex_init(&tpnt->lock); - st_nr_dev++; - write_unlock(&st_dev_arr_lock); + if (!idr_pre_get(&st_index_idr, GFP_KERNEL)) { + pr_warn("st: idr expansion failed\n"); + error = -ENOMEM; + goto out_put_disk; + } + + spin_lock(&st_index_lock); + error = idr_get_new(&st_index_idr, tpnt, &dev_num); + spin_unlock(&st_index_lock); + if (error) { + pr_warn("st: idr allocation failed: %d\n", error); + goto out_put_disk; + } + + if (dev_num > ST_MAX_TAPES) { + pr_err("st: Too many tape devices (max. %d).\n", ST_MAX_TAPES); + goto out_put_index; + } + + tpnt->index = dev_num; + sprintf(disk->disk_name, "st%d", dev_num); + + dev_set_drvdata(dev, tpnt); for (mode = 0; mode < ST_NBR_MODES; ++mode) { STm = &(tpnt->modes[mode]); @@ -4189,10 +4166,10 @@ static int st_probe(struct device *dev) return 0; out_free_tape: + sysfs_remove_link(&tpnt->device->sdev_gendev.kobj, + "tape"); for (mode=0; mode < ST_NBR_MODES; mode++) { STm = &(tpnt->modes[mode]); - sysfs_remove_link(&tpnt->device->sdev_gendev.kobj, - "tape"); for (j=0; j < 2; j++) { if (STm->cdevs[j]) { device_destroy(&st_sysfs_class, @@ -4202,10 +4179,10 @@ out_free_tape: } } } - write_lock(&st_dev_arr_lock); - scsi_tapes[dev_num] = NULL; - st_nr_dev--; - write_unlock(&st_dev_arr_lock); +out_put_index: + spin_lock(&st_index_lock); + idr_remove(&st_index_idr, dev_num); + spin_unlock(&st_index_lock); out_put_disk: put_disk(disk); kfree(tpnt); @@ -4218,38 +4195,32 @@ out: static int st_remove(struct device *dev) { - struct scsi_device *SDp = to_scsi_device(dev); - struct scsi_tape *tpnt; - int i, j, mode; - - scsi_autopm_get_device(SDp); - write_lock(&st_dev_arr_lock); - for (i = 0; i < st_dev_max; i++) { - tpnt = scsi_tapes[i]; - if (tpnt != NULL && tpnt->device == SDp) { - scsi_tapes[i] = NULL; - st_nr_dev--; - write_unlock(&st_dev_arr_lock); - sysfs_remove_link(&tpnt->device->sdev_gendev.kobj, - "tape"); - for (mode = 0; mode < ST_NBR_MODES; ++mode) { - for (j=0; j < 2; j++) { - device_destroy(&st_sysfs_class, - MKDEV(SCSI_TAPE_MAJOR, - TAPE_MINOR(i, mode, j))); - cdev_del(tpnt->modes[mode].cdevs[j]); - tpnt->modes[mode].cdevs[j] = NULL; - } - } - - mutex_lock(&st_ref_mutex); - kref_put(&tpnt->kref, scsi_tape_release); - mutex_unlock(&st_ref_mutex); - return 0; + struct scsi_tape *tpnt = dev_get_drvdata(dev); + int rew, mode; + dev_t cdev_devno; + struct cdev *cdev; + int index = tpnt->index; + + scsi_autopm_get_device(to_scsi_device(dev)); + sysfs_remove_link(&tpnt->device->sdev_gendev.kobj, "tape"); + for (mode = 0; mode < ST_NBR_MODES; ++mode) { + for (rew = 0; rew < 2; rew++) { + cdev = tpnt->modes[mode].cdevs[rew]; + if (!cdev) + continue; + cdev_devno = cdev->dev; + device_destroy(&st_sysfs_class, cdev_devno); + cdev_del(tpnt->modes[mode].cdevs[rew]); + tpnt->modes[mode].cdevs[rew] = NULL; } } - write_unlock(&st_dev_arr_lock); + mutex_lock(&st_ref_mutex); + kref_put(&tpnt->kref, scsi_tape_release); + mutex_unlock(&st_ref_mutex); + spin_lock(&st_index_lock); + idr_remove(&st_index_idr, index); + spin_unlock(&st_index_lock); return 0; } @@ -4336,7 +4307,6 @@ static void __exit exit_st(void) unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0), ST_MAX_TAPE_ENTRIES); class_unregister(&st_sysfs_class); - kfree(scsi_tapes); printk(KERN_INFO "st: Unloaded.\n"); } @@ -4459,22 +4429,10 @@ static ssize_t options_show(struct device *dev, struct device_attribute *attr, char *buf) { struct st_modedef *STm = dev_get_drvdata(dev); - struct scsi_tape *STp; - int i, j, options; + struct scsi_tape *STp = STm->tape; + int options; ssize_t l = 0; - for (i=0; i < st_dev_max; i++) { - for (j=0; j < ST_NBR_MODES; j++) - if (&scsi_tapes[i]->modes[j] == STm) - break; - if (j < ST_NBR_MODES) - break; - } - if (i == st_dev_max) - return 0; /* should never happen */ - - STp = scsi_tapes[i]; - options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0; options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0; options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0; diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h index b548923785ed..8a23640981c8 100644 --- a/drivers/scsi/st.h +++ b/drivers/scsi/st.h @@ -66,6 +66,7 @@ struct st_modedef { unsigned char default_compression; /* 0 = don't touch, etc */ short default_density; /* Forced density, -1 = no value */ int default_blksize; /* Forced blocksize, -1 = no value */ + struct scsi_tape *tape; struct cdev *cdevs[2]; /* Auto-rewind and non-rewind devices */ }; @@ -99,6 +100,7 @@ struct scsi_tape { struct mutex lock; /* For serialization */ struct completion wait; /* For SCSI commands */ struct st_buffer *buffer; + int index; /* Drive characteristics */ unsigned char omit_blklims; -- 2.20.1