From 6038f373a3dc1f1c26496e60b6c40b164716f07e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sun, 15 Aug 2010 18:52:59 +0200 Subject: llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann Cc: Julia Lawall Cc: Christoph Hellwig --- fs/coda/psdev.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/coda/psdev.c') diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c index de89645777c7..9fa280bfcffe 100644 --- a/fs/coda/psdev.c +++ b/fs/coda/psdev.c @@ -346,6 +346,7 @@ static const struct file_operations coda_psdev_fops = { .unlocked_ioctl = coda_psdev_ioctl, .open = coda_psdev_open, .release = coda_psdev_release, + .llseek = noop_llseek, }; static int init_coda_psdev(void) -- cgit v1.2.3 From f7cc02b8715618e179242ba9cc10bdc5146ae565 Mon Sep 17 00:00:00 2001 From: Yoshihisa Abe Date: Mon, 25 Oct 2010 02:03:45 -0400 Subject: Coda: push BKL regions into coda_upcall() Now that shared inode state is locked using the cii->c_lock, the BKL is only used to protect the upcall queues used to communicate with the userspace cache manager. The remaining state is all local and we can push the lock further down into coda_upcall(). Signed-off-by: Yoshihisa Abe Signed-off-by: Jan Harkes Signed-off-by: Linus Torvalds --- fs/coda/psdev.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) (limited to 'fs/coda/psdev.c') diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c index fdc2f3ef7ecd..9a9248e632c6 100644 --- a/fs/coda/psdev.c +++ b/fs/coda/psdev.c @@ -108,16 +108,9 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, return -EFAULT; if (DOWNCALL(hdr.opcode)) { - struct super_block *sb = NULL; - union outputArgs *dcbuf; + union outputArgs *dcbuf; int size = sizeof(*dcbuf); - sb = vcp->vc_sb; - if ( !sb ) { - count = nbytes; - goto out; - } - if ( nbytes < sizeof(struct coda_out_hdr) ) { printk("coda_downcall opc %d uniq %d, not enough!\n", hdr.opcode, hdr.unique); @@ -137,9 +130,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, } /* what downcall errors does Venus handle ? */ - lock_kernel(); - error = coda_downcall(hdr.opcode, dcbuf, sb); - unlock_kernel(); + error = coda_downcall(vcp, hdr.opcode, dcbuf); CODA_FREE(dcbuf, nbytes); if (error) { -- cgit v1.2.3 From da47c19e5c746829042933c8f945a71e2b62d6fc Mon Sep 17 00:00:00 2001 From: Yoshihisa Abe Date: Mon, 25 Oct 2010 02:03:46 -0400 Subject: Coda: replace BKL with mutex Replace the BKL with a mutex to protect the venus_comm structure which binds the mountpoint with the character device and holds the upcall queues. Signed-off-by: Yoshihisa Abe Signed-off-by: Jan Harkes Signed-off-by: Linus Torvalds --- fs/coda/psdev.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) (limited to 'fs/coda/psdev.c') diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c index 9a9248e632c6..62647a8595e4 100644 --- a/fs/coda/psdev.c +++ b/fs/coda/psdev.c @@ -35,7 +35,7 @@ #include #include #include -#include +#include #include #include #include @@ -67,8 +67,10 @@ static unsigned int coda_psdev_poll(struct file *file, poll_table * wait) unsigned int mask = POLLOUT | POLLWRNORM; poll_wait(file, &vcp->vc_waitq, wait); + mutex_lock(&vcp->vc_mutex); if (!list_empty(&vcp->vc_pending)) mask |= POLLIN | POLLRDNORM; + mutex_unlock(&vcp->vc_mutex); return mask; } @@ -143,7 +145,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, } /* Look for the message on the processing queue. */ - lock_kernel(); + mutex_lock(&vcp->vc_mutex); list_for_each(lh, &vcp->vc_processing) { tmp = list_entry(lh, struct upc_req , uc_chain); if (tmp->uc_unique == hdr.unique) { @@ -152,7 +154,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, break; } } - unlock_kernel(); + mutex_unlock(&vcp->vc_mutex); if (!req) { printk("psdev_write: msg (%d, %d) not found\n", @@ -207,7 +209,7 @@ static ssize_t coda_psdev_read(struct file * file, char __user * buf, if (nbytes == 0) return 0; - lock_kernel(); + mutex_lock(&vcp->vc_mutex); add_wait_queue(&vcp->vc_waitq, &wait); set_current_state(TASK_INTERRUPTIBLE); @@ -221,7 +223,9 @@ static ssize_t coda_psdev_read(struct file * file, char __user * buf, retval = -ERESTARTSYS; break; } + mutex_unlock(&vcp->vc_mutex); schedule(); + mutex_lock(&vcp->vc_mutex); } set_current_state(TASK_RUNNING); @@ -254,7 +258,7 @@ static ssize_t coda_psdev_read(struct file * file, char __user * buf, CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr)); kfree(req); out: - unlock_kernel(); + mutex_unlock(&vcp->vc_mutex); return (count ? count : retval); } @@ -267,10 +271,10 @@ static int coda_psdev_open(struct inode * inode, struct file * file) if (idx < 0 || idx >= MAX_CODADEVS) return -ENODEV; - lock_kernel(); - err = -EBUSY; vcp = &coda_comms[idx]; + mutex_lock(&vcp->vc_mutex); + if (!vcp->vc_inuse) { vcp->vc_inuse++; @@ -284,7 +288,7 @@ static int coda_psdev_open(struct inode * inode, struct file * file) err = 0; } - unlock_kernel(); + mutex_unlock(&vcp->vc_mutex); return err; } @@ -299,7 +303,7 @@ static int coda_psdev_release(struct inode * inode, struct file * file) return -1; } - lock_kernel(); + mutex_lock(&vcp->vc_mutex); /* Wakeup clients so they can return. */ list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { @@ -324,7 +328,7 @@ static int coda_psdev_release(struct inode * inode, struct file * file) file->private_data = NULL; vcp->vc_inuse--; - unlock_kernel(); + mutex_unlock(&vcp->vc_mutex); return 0; } @@ -353,9 +357,11 @@ static int init_coda_psdev(void) err = PTR_ERR(coda_psdev_class); goto out_chrdev; } - for (i = 0; i < MAX_CODADEVS; i++) + for (i = 0; i < MAX_CODADEVS; i++) { + mutex_init(&(&coda_comms[i])->vc_mutex); device_create(coda_psdev_class, NULL, MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); + } coda_sysctl_init(); goto out; -- cgit v1.2.3