Re: 2.4.2-ac3: loop threads in D state

From: Jens Axboe (axboe@suse.de)
Date: Sun Feb 25 2001 - 19:24:30 EST


On Sun, Feb 25 2001, Alexander Viro wrote:
> Jens, you have a race in lo_clr_fd() (loop-6). I've put the fixed
> variant on ftp.math.psu.edu/pub/viro/loop-S2.gz. Diff and you'll
> see - it's in the very beginning of the lo_clr_fd().

Oops yeah you are right. Here's a diff of my current loop stuff
against -ac4, Alan could you apply? Andrea suggested removing
the loop private slab cache for buffer heads and just using the
bh_cachep pool, and it seems like a good idea to me.

-- 
Jens Axboe

diff -ur --exclude-from /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.2-ac4/drivers/block/loop.c linux/drivers/block/loop.c --- /opt/kernel/linux-2.4.2-ac4/drivers/block/loop.c Mon Feb 26 01:19:38 2001 +++ linux/drivers/block/loop.c Mon Feb 26 01:22:28 2001 @@ -79,7 +79,6 @@ static int *loop_sizes; static int *loop_blksizes; static devfs_handle_t devfs_handle; /* For the directory */ -static kmem_cache_t *loop_bhp; /* * Transfer functions @@ -289,7 +288,7 @@ if (bh) { kunmap(bh->b_page); __free_page(bh->b_page); - kmem_cache_free(loop_bhp, bh); + kmem_cache_free(bh_cachep, bh); } } @@ -358,7 +357,7 @@ struct buffer_head *bh; do { - bh = kmem_cache_alloc(loop_bhp, SLAB_BUFFER); + bh = kmem_cache_alloc(bh_cachep, SLAB_BUFFER); if (bh) break; @@ -508,7 +507,7 @@ sprintf(current->comm, "loop%d", lo->lo_number); spin_lock_irq(&current->sigmask_lock); - siginitsetinv(&current->blocked, sigmask(SIGKILL)); + sigfillset(&current->blocked); flush_signals(current); spin_unlock_irq(&current->sigmask_lock); @@ -526,7 +525,7 @@ up(&lo->lo_sem); for (;;) { - down(&lo->lo_bh_mutex); + down_interruptible(&lo->lo_bh_mutex); if (!atomic_read(&lo->lo_pending)) break; @@ -671,9 +670,12 @@ if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */ return -EBUSY; + spin_lock_irq(&lo->lo_lock); lo->lo_state = Lo_rundown; atomic_dec(&lo->lo_pending); up(&lo->lo_bh_mutex); + spin_unlock_irq(&lo->lo_lock); + down(&lo->lo_sem); lo->lo_backing_file = NULL; @@ -927,13 +929,6 @@ return -EIO; } - loop_bhp = kmem_cache_create("loop_buffers", sizeof(struct buffer_head), - 0, SLAB_HWCACHE_ALIGN, NULL, NULL); - if (!loop_bhp) { - printk(KERN_WARNING "loop: unable to create slab cache\n"); - return -ENOMEM; - } - devfs_handle = devfs_mk_dir(NULL, "loop", NULL); devfs_register_series(devfs_handle, "%u", max_loop, DEVFS_FL_DEFAULT, MAJOR_NR, 0, @@ -942,7 +937,7 @@ loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL); if (!loop_dev) - goto out_dev; + return -ENOMEM; loop_sizes = kmalloc(max_loop * sizeof(int), GFP_KERNEL); if (!loop_sizes) @@ -974,8 +969,6 @@ printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop); return 0; -out_dev: - kmem_cache_destroy(loop_bhp); out_sizes: kfree(loop_dev); out_blksizes: @@ -990,7 +983,6 @@ if (devfs_unregister_blkdev(MAJOR_NR, "loop")) printk(KERN_WARNING "loop: cannot unregister blkdev\n"); - kmem_cache_destroy(loop_bhp); kfree(loop_dev); kfree(loop_sizes); kfree(loop_blksizes); diff -ur --exclude-from /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.2-ac4/fs/Makefile linux/fs/Makefile --- /opt/kernel/linux-2.4.2-ac4/fs/Makefile Mon Feb 26 01:19:40 2001 +++ linux/fs/Makefile Mon Feb 26 01:14:44 2001 @@ -7,7 +7,7 @@ O_TARGET := fs.o -export-objs := filesystems.o open.o +export-objs := filesystems.o open.o dcache.o mod-subdirs := nls obj-y := open.o read_write.o devices.o file_table.o buffer.o \ diff -ur --exclude-from /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.2-ac4/fs/dcache.c linux/fs/dcache.c --- /opt/kernel/linux-2.4.2-ac4/fs/dcache.c Sat Feb 17 01:06:17 2001 +++ linux/fs/dcache.c Mon Feb 26 01:14:54 2001 @@ -22,6 +22,7 @@ #include <linux/init.h> #include <linux/smp_lock.h> #include <linux/cache.h> +#include <linux/module.h> #include <asm/uaccess.h> @@ -1250,6 +1251,7 @@ /* SLAB cache for buffer_head structures */ kmem_cache_t *bh_cachep; +EXPORT_SYMBOL(bh_cachep); void __init vfs_caches_init(unsigned long mempages) {

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This archive was generated by hypermail 2b29 : Wed Feb 28 2001 - 21:00:10 EST