PATCH - md 14 of 22 - Second step to tidying mddev refcounts and locking
From: Neil Brown <hidden>
Date: 2002-06-19 00:53:09
This patch gets md_open to use mddev_find instead of kdev_to_mddev, thus creating the mddev if necessary. This guarantees that md_release will be able to find an mddev to mddev_put. Now that we are certain of getting the refcount right at open/close time, we don't need the "countdev" stuff. If START_ARRAY happens to start and array other than that the one that is currently opened, it won't confuse things at all. ----------- Diffstat output ------------ ./drivers/md/md.c | 32 +++++++++++++++++--------------- 1 files changed, 17 insertions(+), 15 deletions(-)
--- ./drivers/md/md.c 2002/06/18 04:40:56 1.13
+++ ./drivers/md/md.c 2002/06/18 04:47:43 1.14@@ -1809,7 +1809,7 @@ * * If "unit" is allocated, then bump its reference count */ -static void autorun_devices(kdev_t countdev) +static void autorun_devices(void) { struct list_head candidates; struct list_head *tmp;
@@ -1863,9 +1863,7 @@ list_del_init(&rdev->pending); } autorun_array(mddev); - if (minor(countdev) != mdidx(mddev)) - mddev_put(mddev); - /* else put will happen at md_close time */ + mddev_put(mddev); } printk(KERN_INFO "md: ... autorun DONE.\n"); }
@@ -1902,7 +1900,7 @@ #define AUTORUNNING KERN_INFO \ "md: auto-running md%d.\n" -static int autostart_array(kdev_t startdev, kdev_t countdev) +static int autostart_array(kdev_t startdev) { int err = -EINVAL, i; mdp_super_t *sb = NULL;
@@ -1962,7 +1960,7 @@ /* * possibly return codes */ - autorun_devices(countdev); + autorun_devices(); return 0; abort:
@@ -2549,7 +2547,7 @@ /* * possibly make it lock the array ... */ - err = autostart_array(val_to_kdev(arg), dev); + err = autostart_array(val_to_kdev(arg)); if (err) { printk(KERN_WARNING "md: autostart %s failed!\n", partition_name(val_to_kdev(arg)));
@@ -2701,19 +2699,23 @@ static int md_open(struct inode *inode, struct file *file) { /* - * Always succeed, but increment the usage count + * Succeed if we can find or allocate a mddev structure. */ - mddev_t *mddev = kdev_to_mddev(inode->i_rdev); - if (mddev) - mddev_get(mddev); - return (0); + mddev_t *mddev = mddev_find(minor(inode->i_rdev)); + + if (mddev) + return 0; /* and we "own" a reference */ + else + return -ENOMEM; } static int md_release(struct inode *inode, struct file * file) { mddev_t *mddev = kdev_to_mddev(inode->i_rdev); - if (mddev) - mddev_put(mddev); + if (!mddev) + BUG(); + mddev_put(mddev); + return 0; }
@@ -3548,7 +3550,7 @@ } dev_cnt = 0; - autorun_devices(to_kdev_t(-1)); + autorun_devices(); } static struct {