| Message ID | 20171004091007.26729-1-linus.walleij@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 4 October 2017 at 11:10, Linus Walleij <linus.walleij@linaro.org> wrote: > I forgot to account for the fact that the device core holds a > reference to a device added with device_initialize() that need > to be released with a corresponding put_device() to reach a 0 > refcount at the end of the lifecycle. > > This led to a NULL pointer reference when freeing the device > when e.g. unbidning the host device in sysfs. > > Fix this and use the device .release() callback to free the > IDA and free:ing the memory used by the RPMB device. > > Before this patch: > > /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind > [ 29.797332] mmc3: card 0001 removed > [ 29.810791] Unable to handle kernel NULL pointer dereference at > virtual address 00000050 > [ 29.818878] pgd = de70c000 > [ 29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000 > [ 29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM > [ 29.833282] Modules linked in: > [ 29.836334] CPU: 1 PID: 154 Comm: sh Not tainted > 4.14.0-rc3-00039-g83318e309566-dirty #736 > [ 29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support) > [ 29.851562] task: de572700 task.stack: de742000 > [ 29.856079] PC is at kernfs_find_ns+0x8/0x100 > [ 29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48 > > After this patch: > > /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind > [ 20.623382] mmc3: card 0001 removed > > Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device") > Reported-by: Adrian Hunter <adrian.hunter@intel.com> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> This looks good to me. However I wait a bit to get an ack from Adrian as well - before I queue this up for fixes! Kind regards Uffe > --- > ChangeLog v3->v4: > - Also skip the lock now that we take it inside mmc_blk_get()/ > mmc_blk_put() > ChangeLog v2->v3: > - Fix the block device reference counting: instead of manipulating > md->usage directly, call the proper refcounting functions > mmc_blk_get() and mmc_blk_put(). > ChangeLog v1->v2: > - Drop the print from removing the RPMB partition > - Refactor the error path of the RPMB to use refcounting > - Drop the verbose comment on refcounts > --- > drivers/mmc/core/block.c | 32 ++++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c > index c29dbcec7c61..ea80ff4cd7f9 100644 > --- a/drivers/mmc/core/block.c > +++ b/drivers/mmc/core/block.c > @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp) > > get_device(&rpmb->dev); > filp->private_data = rpmb; > - mutex_lock(&open_lock); > - rpmb->md->usage++; > - mutex_unlock(&open_lock); > + mmc_blk_get(rpmb->md->disk); > > return nonseekable_open(inode, filp); > } > @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp) > struct mmc_rpmb_data, chrdev); > > put_device(&rpmb->dev); > - mutex_lock(&open_lock); > - rpmb->md->usage--; > - mutex_unlock(&open_lock); > + mmc_blk_put(rpmb->md); > > return 0; > } > @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = { > #endif > }; > > +static void mmc_blk_rpmb_device_release(struct device *dev) > +{ > + struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev); > + > + ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > + kfree(rpmb); > +} > > static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > struct mmc_blk_data *md, > @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > return devidx; > > rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL); > - if (!rpmb) > + if (!rpmb) { > + ida_simple_remove(&mmc_rpmb_ida, devidx); > return -ENOMEM; > + } > > snprintf(rpmb_name, sizeof(rpmb_name), > "mmcblk%u%s", card->host->index, subname ? subname : ""); > @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > rpmb->dev.bus = &mmc_rpmb_bus_type; > rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id); > rpmb->dev.parent = &card->dev; > + rpmb->dev.release = mmc_blk_rpmb_device_release; > device_initialize(&rpmb->dev); > dev_set_drvdata(&rpmb->dev, rpmb); > rpmb->md = md; > @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev); > if (ret) { > pr_err("%s: could not add character device\n", rpmb_name); > - goto out_remove_ida; > + goto out_put_device; > } > > list_add(&rpmb->node, &md->rpmbs); > @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > > return 0; > > -out_remove_ida: > - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > - kfree(rpmb); > +out_put_device: > + put_device(&rpmb->dev); > return ret; > } > > static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb) > + > { > cdev_device_del(&rpmb->chrdev, &rpmb->dev); > - device_del(&rpmb->dev); > - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > - kfree(rpmb); > + put_device(&rpmb->dev); > } > > /* MMC Physical partitions consist of two boot partitions and > -- > 2.13.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 04/10/17 12:10, Linus Walleij wrote: > I forgot to account for the fact that the device core holds a > reference to a device added with device_initialize() that need > to be released with a corresponding put_device() to reach a 0 > refcount at the end of the lifecycle. > > This led to a NULL pointer reference when freeing the device > when e.g. unbidning the host device in sysfs. > > Fix this and use the device .release() callback to free the > IDA and free:ing the memory used by the RPMB device. > > Before this patch: > > /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind > [ 29.797332] mmc3: card 0001 removed > [ 29.810791] Unable to handle kernel NULL pointer dereference at > virtual address 00000050 > [ 29.818878] pgd = de70c000 > [ 29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000 > [ 29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM > [ 29.833282] Modules linked in: > [ 29.836334] CPU: 1 PID: 154 Comm: sh Not tainted > 4.14.0-rc3-00039-g83318e309566-dirty #736 > [ 29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support) > [ 29.851562] task: de572700 task.stack: de742000 > [ 29.856079] PC is at kernfs_find_ns+0x8/0x100 > [ 29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48 > > After this patch: > > /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind > [ 20.623382] mmc3: card 0001 removed > > Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device") > Reported-by: Adrian Hunter <adrian.hunter@intel.com> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Adrian Hunter <adrian.hunter@intel.com> > --- > ChangeLog v3->v4: > - Also skip the lock now that we take it inside mmc_blk_get()/ > mmc_blk_put() > ChangeLog v2->v3: > - Fix the block device reference counting: instead of manipulating > md->usage directly, call the proper refcounting functions > mmc_blk_get() and mmc_blk_put(). > ChangeLog v1->v2: > - Drop the print from removing the RPMB partition > - Refactor the error path of the RPMB to use refcounting > - Drop the verbose comment on refcounts > --- > drivers/mmc/core/block.c | 32 ++++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c > index c29dbcec7c61..ea80ff4cd7f9 100644 > --- a/drivers/mmc/core/block.c > +++ b/drivers/mmc/core/block.c > @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp) > > get_device(&rpmb->dev); > filp->private_data = rpmb; > - mutex_lock(&open_lock); > - rpmb->md->usage++; > - mutex_unlock(&open_lock); > + mmc_blk_get(rpmb->md->disk); > > return nonseekable_open(inode, filp); > } > @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp) > struct mmc_rpmb_data, chrdev); > > put_device(&rpmb->dev); > - mutex_lock(&open_lock); > - rpmb->md->usage--; > - mutex_unlock(&open_lock); > + mmc_blk_put(rpmb->md); > > return 0; > } > @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = { > #endif > }; > > +static void mmc_blk_rpmb_device_release(struct device *dev) > +{ > + struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev); > + > + ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > + kfree(rpmb); > +} > > static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > struct mmc_blk_data *md, > @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > return devidx; > > rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL); > - if (!rpmb) > + if (!rpmb) { > + ida_simple_remove(&mmc_rpmb_ida, devidx); > return -ENOMEM; > + } > > snprintf(rpmb_name, sizeof(rpmb_name), > "mmcblk%u%s", card->host->index, subname ? subname : ""); > @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > rpmb->dev.bus = &mmc_rpmb_bus_type; > rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id); > rpmb->dev.parent = &card->dev; > + rpmb->dev.release = mmc_blk_rpmb_device_release; > device_initialize(&rpmb->dev); > dev_set_drvdata(&rpmb->dev, rpmb); > rpmb->md = md; > @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev); > if (ret) { > pr_err("%s: could not add character device\n", rpmb_name); > - goto out_remove_ida; > + goto out_put_device; > } > > list_add(&rpmb->node, &md->rpmbs); > @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > > return 0; > > -out_remove_ida: > - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > - kfree(rpmb); > +out_put_device: > + put_device(&rpmb->dev); > return ret; > } > > static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb) > + > { > cdev_device_del(&rpmb->chrdev, &rpmb->dev); > - device_del(&rpmb->dev); > - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > - kfree(rpmb); > + put_device(&rpmb->dev); > } > > /* MMC Physical partitions consist of two boot partitions and > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 4 October 2017 at 11:10, Linus Walleij <linus.walleij@linaro.org> wrote: > I forgot to account for the fact that the device core holds a > reference to a device added with device_initialize() that need > to be released with a corresponding put_device() to reach a 0 > refcount at the end of the lifecycle. > > This led to a NULL pointer reference when freeing the device > when e.g. unbidning the host device in sysfs. > > Fix this and use the device .release() callback to free the > IDA and free:ing the memory used by the RPMB device. > > Before this patch: > > /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind > [ 29.797332] mmc3: card 0001 removed > [ 29.810791] Unable to handle kernel NULL pointer dereference at > virtual address 00000050 > [ 29.818878] pgd = de70c000 > [ 29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000 > [ 29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM > [ 29.833282] Modules linked in: > [ 29.836334] CPU: 1 PID: 154 Comm: sh Not tainted > 4.14.0-rc3-00039-g83318e309566-dirty #736 > [ 29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support) > [ 29.851562] task: de572700 task.stack: de742000 > [ 29.856079] PC is at kernfs_find_ns+0x8/0x100 > [ 29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48 > > After this patch: > > /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind > [ 20.623382] mmc3: card 0001 removed > > Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device") > Reported-by: Adrian Hunter <adrian.hunter@intel.com> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Thanks, applied for next! Kind regards Uffe > --- > ChangeLog v3->v4: > - Also skip the lock now that we take it inside mmc_blk_get()/ > mmc_blk_put() > ChangeLog v2->v3: > - Fix the block device reference counting: instead of manipulating > md->usage directly, call the proper refcounting functions > mmc_blk_get() and mmc_blk_put(). > ChangeLog v1->v2: > - Drop the print from removing the RPMB partition > - Refactor the error path of the RPMB to use refcounting > - Drop the verbose comment on refcounts > --- > drivers/mmc/core/block.c | 32 ++++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c > index c29dbcec7c61..ea80ff4cd7f9 100644 > --- a/drivers/mmc/core/block.c > +++ b/drivers/mmc/core/block.c > @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp) > > get_device(&rpmb->dev); > filp->private_data = rpmb; > - mutex_lock(&open_lock); > - rpmb->md->usage++; > - mutex_unlock(&open_lock); > + mmc_blk_get(rpmb->md->disk); > > return nonseekable_open(inode, filp); > } > @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp) > struct mmc_rpmb_data, chrdev); > > put_device(&rpmb->dev); > - mutex_lock(&open_lock); > - rpmb->md->usage--; > - mutex_unlock(&open_lock); > + mmc_blk_put(rpmb->md); > > return 0; > } > @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = { > #endif > }; > > +static void mmc_blk_rpmb_device_release(struct device *dev) > +{ > + struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev); > + > + ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > + kfree(rpmb); > +} > > static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > struct mmc_blk_data *md, > @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > return devidx; > > rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL); > - if (!rpmb) > + if (!rpmb) { > + ida_simple_remove(&mmc_rpmb_ida, devidx); > return -ENOMEM; > + } > > snprintf(rpmb_name, sizeof(rpmb_name), > "mmcblk%u%s", card->host->index, subname ? subname : ""); > @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > rpmb->dev.bus = &mmc_rpmb_bus_type; > rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id); > rpmb->dev.parent = &card->dev; > + rpmb->dev.release = mmc_blk_rpmb_device_release; > device_initialize(&rpmb->dev); > dev_set_drvdata(&rpmb->dev, rpmb); > rpmb->md = md; > @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev); > if (ret) { > pr_err("%s: could not add character device\n", rpmb_name); > - goto out_remove_ida; > + goto out_put_device; > } > > list_add(&rpmb->node, &md->rpmbs); > @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, > > return 0; > > -out_remove_ida: > - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > - kfree(rpmb); > +out_put_device: > + put_device(&rpmb->dev); > return ret; > } > > static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb) > + > { > cdev_device_del(&rpmb->chrdev, &rpmb->dev); > - device_del(&rpmb->dev); > - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); > - kfree(rpmb); > + put_device(&rpmb->dev); > } > > /* MMC Physical partitions consist of two boot partitions and > -- > 2.13.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index c29dbcec7c61..ea80ff4cd7f9 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp) get_device(&rpmb->dev); filp->private_data = rpmb; - mutex_lock(&open_lock); - rpmb->md->usage++; - mutex_unlock(&open_lock); + mmc_blk_get(rpmb->md->disk); return nonseekable_open(inode, filp); } @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp) struct mmc_rpmb_data, chrdev); put_device(&rpmb->dev); - mutex_lock(&open_lock); - rpmb->md->usage--; - mutex_unlock(&open_lock); + mmc_blk_put(rpmb->md); return 0; } @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = { #endif }; +static void mmc_blk_rpmb_device_release(struct device *dev) +{ + struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev); + + ida_simple_remove(&mmc_rpmb_ida, rpmb->id); + kfree(rpmb); +} static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, struct mmc_blk_data *md, @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, return devidx; rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL); - if (!rpmb) + if (!rpmb) { + ida_simple_remove(&mmc_rpmb_ida, devidx); return -ENOMEM; + } snprintf(rpmb_name, sizeof(rpmb_name), "mmcblk%u%s", card->host->index, subname ? subname : ""); @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, rpmb->dev.bus = &mmc_rpmb_bus_type; rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id); rpmb->dev.parent = &card->dev; + rpmb->dev.release = mmc_blk_rpmb_device_release; device_initialize(&rpmb->dev); dev_set_drvdata(&rpmb->dev, rpmb); rpmb->md = md; @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev); if (ret) { pr_err("%s: could not add character device\n", rpmb_name); - goto out_remove_ida; + goto out_put_device; } list_add(&rpmb->node, &md->rpmbs); @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, return 0; -out_remove_ida: - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); - kfree(rpmb); +out_put_device: + put_device(&rpmb->dev); return ret; } static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb) + { cdev_device_del(&rpmb->chrdev, &rpmb->dev); - device_del(&rpmb->dev); - ida_simple_remove(&mmc_rpmb_ida, rpmb->id); - kfree(rpmb); + put_device(&rpmb->dev); } /* MMC Physical partitions consist of two boot partitions and
I forgot to account for the fact that the device core holds a reference to a device added with device_initialize() that need to be released with a corresponding put_device() to reach a 0 refcount at the end of the lifecycle. This led to a NULL pointer reference when freeing the device when e.g. unbidning the host device in sysfs. Fix this and use the device .release() callback to free the IDA and free:ing the memory used by the RPMB device. Before this patch: /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind [ 29.797332] mmc3: card 0001 removed [ 29.810791] Unable to handle kernel NULL pointer dereference at virtual address 00000050 [ 29.818878] pgd = de70c000 [ 29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000 [ 29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM [ 29.833282] Modules linked in: [ 29.836334] CPU: 1 PID: 154 Comm: sh Not tainted 4.14.0-rc3-00039-g83318e309566-dirty #736 [ 29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support) [ 29.851562] task: de572700 task.stack: de742000 [ 29.856079] PC is at kernfs_find_ns+0x8/0x100 [ 29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48 After this patch: /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind [ 20.623382] mmc3: card 0001 removed Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device") Reported-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- ChangeLog v3->v4: - Also skip the lock now that we take it inside mmc_blk_get()/ mmc_blk_put() ChangeLog v2->v3: - Fix the block device reference counting: instead of manipulating md->usage directly, call the proper refcounting functions mmc_blk_get() and mmc_blk_put(). ChangeLog v1->v2: - Drop the print from removing the RPMB partition - Refactor the error path of the RPMB to use refcounting - Drop the verbose comment on refcounts --- drivers/mmc/core/block.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-)