This commit replaces an empty device releases callback with
one that uses reference counter to free underlying memory
only when the device is no longer used.
Signed-off-by: Michal Nazarewicz <m.nazarewicz@xxxxxxxxxxx>
---
drivers/usb/gadget/f_mass_storage.c | 87 +++++++++++++++++++++++------------
1 files changed, 57 insertions(+), 30 deletions(-)
This is put on top of the other 7 patches I sent earlier.
Noticed this after the put_device() fix, turns out 9-hour flight is
just perfect for fixing bugs (that, plus movies were boring).
Greg,
It seems it does not qualify for stable (too long); if you decide to pull
it into stable anyway (since a lot changes are just a simple
s/luns/luns->arr/) drop me a line so I'll rebase it.
diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index b5dbb23..a3f7e71 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -349,9 +349,6 @@ struct fsg_common {
struct fsg_dev *fsg, *new_fsg;
wait_queue_head_t fsg_wait;
- /* filesem protects: backing files in use */
- struct rw_semaphore filesem;
-
/* lock protects: state, all the req_busy's */
spinlock_t lock;
@@ -368,7 +365,12 @@ struct fsg_common {
unsigned int nluns;
unsigned int lun;
- struct fsg_lun *luns;
+ struct fsg_luns {
+ /* filesem protects: backing files in use */
+ struct rw_semaphore filesem;
+ struct kref ref;
+ struct fsg_lun arr[];
+ } *luns;
struct fsg_lun *curlun;
unsigned int bulk_out_maxpacket;
@@ -1465,22 +1467,22 @@ static int do_start_stop(struct fsg_common *common)
/* Simulate an unload/eject */
if (common->ops && common->ops->pre_eject) {
int r = common->ops->pre_eject(common, curlun,
- curlun - common->luns);
+ curlun - common->luns->arr);
if (unlikely(r < 0))
return r;
else if (r)
return 0;
}
- up_read(&common->filesem);
- down_write(&common->filesem);
+ up_read(&common->luns->filesem);
+ down_write(&common->luns->filesem);
fsg_lun_close(curlun);
- up_write(&common->filesem);
- down_read(&common->filesem);
+ up_write(&common->luns->filesem);
+ down_read(&common->luns->filesem);
return common->ops && common->ops->post_eject
? min(0, common->ops->post_eject(common, curlun,
- curlun - common->luns))
+ curlun - common->luns->arr))
: 0;
}
@@ -1910,7 +1912,7 @@ static int check_command(struct fsg_common *common, int cmnd_size,
/* Check the LUN */
if (common->lun >= 0 && common->lun < common->nluns) {
- curlun = &common->luns[common->lun];
+ curlun = &common->luns->arr[common->lun];
common->curlun = curlun;
if (common->cmnd[0] != REQUEST_SENSE) {
curlun->sense_data = SS_NO_SENSE;
@@ -1986,7 +1988,8 @@ static int do_scsi_command(struct fsg_common *common)
common->phase_error = 0;
common->short_packet_received = 0;
- down_read(&common->filesem); /* We're using the backing file */
+ /* We're using the backing file */
+ down_read(&common->luns->filesem);
switch (common->cmnd[0]) {
case INQUIRY:
@@ -2219,7 +2222,7 @@ unknown_cmnd:
}
break;
}
- up_read(&common->filesem);
+ up_read(&common->luns->filesem);
if (reply == -EINTR || signal_pending(current))
return -EINTR;
@@ -2455,7 +2458,7 @@ reset:
common->running = 1;
for (i = 0; i < common->nluns; ++i)
- common->luns[i].unit_attention_data = SS_RESET_OCCURRED;
+ common->luns->arr[i].unit_attention_data = SS_RESET_OCCURRED;
return rc;
}
@@ -2555,7 +2558,7 @@ static void handle_exception(struct fsg_common *common)
common->state = FSG_STATE_STATUS_PHASE;
else {
for (i = 0; i < common->nluns; ++i) {
- curlun = &common->luns[i];
+ curlun = &common->luns->arr[i];
curlun->prevent_medium_removal = 0;
curlun->sense_data = SS_NO_SENSE;
curlun->unit_attention_data = SS_NO_SENSE;
@@ -2597,7 +2600,7 @@ static void handle_exception(struct fsg_common *common)
* CONFIG_CHANGE cases.
*/
/* for (i = 0; i < common->nluns; ++i) */
- /* common->luns[i].unit_attention_data = */
+ /* common->luns->arr[i].unit_attention_data = */
/* SS_RESET_OCCURRED; */
break;
@@ -2692,10 +2695,10 @@ static int fsg_main_thread(void *common_)
if (!common->ops || !common->ops->thread_exits
|| common->ops->thread_exits(common) < 0) {
- struct fsg_lun *curlun = common->luns;
+ struct fsg_lun *curlun = common->luns->arr;
unsigned i = common->nluns;
- down_write(&common->filesem);
+ down_write(&common->luns->filesem);
for (; i--; ++curlun) {
if (!fsg_lun_is_open(curlun))
continue;
@@ -2703,7 +2706,7 @@ static int fsg_main_thread(void *common_)
fsg_lun_close(curlun);
curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
}
- up_write(&common->filesem);
+ up_write(&common->luns->filesem);
}
/* Let fsg_unbind() know the thread has exited */
@@ -2723,9 +2726,30 @@ static DEVICE_ATTR(file, 0644, fsg_show_file, fsg_store_file);
static void fsg_common_release(struct kref *ref);
+static void fsg_luns_release(struct kref *ref)
+{
+ struct fsg_luns *luns = container_of(ref, struct fsg_luns, ref);
+ kfree(luns);
+}
+
static void fsg_lun_release(struct device *dev)
{
- /* Nothing needs to be done */
+ struct rw_semaphore *filesem = dev_get_drvdata(dev);
+ struct fsg_luns *luns =
+ container_of(filesem, struct fsg_luns, filesem);
+
+ /*
+ * This should be a no-op but something funky may have
+ * happened and the file may have been opened. Make sure and
+ * coles it.
+ */
+ fsg_lun_close(container_of(dev, struct fsg_lun, dev));
+
+ /*
+ * When all devices are released, the under-laying memory with
+ * accompanying filesem will be freed.
+ */
+ kref_put(&luns->ref, fsg_luns_release);
}
static inline void fsg_common_get(struct fsg_common *common)
@@ -2787,14 +2811,16 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
* Create the LUNs, open their backing files, and register the
* LUN devices in sysfs.
*/
- curlun = kzalloc(nluns * sizeof *curlun, GFP_KERNEL);
- if (unlikely(!curlun)) {
+ common->luns = kzalloc(sizeof *common->luns +
+ nluns * sizeof *common->luns->arr, GFP_KERNEL);
+ if (unlikely(!common->luns)) {
rc = -ENOMEM;
goto error_release;
}
- common->luns = curlun;
+ curlun = common->luns->arr;
- init_rwsem(&common->filesem);
+ init_rwsem(&common->luns->filesem);
+ kref_init(&common->luns->ref);
for (i = 0, lcfg = cfg->luns; i < nluns; ++i, ++curlun, ++lcfg) {
curlun->cdrom = !!lcfg->cdrom;
@@ -2803,13 +2829,14 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
curlun->dev.release = fsg_lun_release;
curlun->dev.parent = &gadget->dev;
/* curlun->dev.driver = &fsg_driver.driver; XXX */
- dev_set_drvdata(&curlun->dev, &common->filesem);
+ dev_set_drvdata(&curlun->dev, &common->luns->filesem);
dev_set_name(&curlun->dev,
cfg->lun_name_format
? cfg->lun_name_format
: "lun%d",
i);
+ kref_get(&common->luns->ref);
rc = device_register(&curlun->dev);
if (rc) {
INFO(common, "failed to register LUN%d: %d\n", i, rc);
@@ -2872,7 +2899,7 @@ buffhds_first_it:
snprintf(common->inquiry_string, sizeof common->inquiry_string,
"%-8s%-16s%04x", cfg->vendor_name ?: "Linux",
/* Assume product name dependent on the first LUN */
- cfg->product_name ?: (common->luns->cdrom
+ cfg->product_name ?: (common->luns->arr->cdrom
? "File-Stor Gadget"
: "File-CD Gadget"),
i);
@@ -2904,7 +2931,7 @@ buffhds_first_it:
INFO(common, "Number of LUNs=%d\n", common->nluns);
pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
- for (i = 0, nluns = common->nluns, curlun = common->luns;
+ for (i = 0, nluns = common->nluns, curlun = common->luns->arr;
i < nluns;
++curlun, ++i) {
char *p = "(no medium)";
@@ -2950,8 +2977,8 @@ static void fsg_common_release(struct kref *ref)
wait_for_completion(&common->thread_notifier);
}
- if (likely(common->luns)) {
- struct fsg_lun *lun = common->luns;
+ if (likely(common->luns->arr)) {
+ struct fsg_lun *lun = common->luns->arr;
unsigned i = common->nluns;
/* In error recovery common->nluns may be zero. */
@@ -2963,7 +2990,7 @@ static void fsg_common_release(struct kref *ref)
device_unregister(&lun->dev);
}
- kfree(common->luns);
+ kref_put(&common->luns->ref, fsg_luns_release);
}
{
--
1.7.2.3
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