From: Latchesar Ionkov Date: Tue, 11 Oct 2005 15:29:03 +0000 (-0700) Subject: [PATCH] v9fs: remove additional buffer allocation from v9fs_file_read and v9fs_file_write X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=19cba8abd6ca09527c194864ae651db65cbacfe1;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git [PATCH] v9fs: remove additional buffer allocation from v9fs_file_read and v9fs_file_write v9fs_file_read and v9fs_file_write use kmalloc to allocate buffers as big as the data buffer received as parameter. kmalloc cannot be used to allocate buffers bigger than 128K, so reading/writing data in chunks bigger than 128k fails. This patch reorganizes v9fs_file_read and v9fs_file_write to allocate only buffers as big as the maximum data that can be sent in one 9P message. Signed-off-by: Latchesar Ionkov Cc: Eric Van Hensbergen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index a4799e971d1c..bbc3cc63854f 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -175,16 +175,16 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl) } /** - * v9fs_read - read from a file (internal) + * v9fs_file_read - read from a file * @filep: file pointer to read * @data: data buffer to read data into * @count: size of buffer * @offset: offset at which to read data * */ - static ssize_t -v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) +v9fs_file_read(struct file *filp, char __user * data, size_t count, + loff_t * offset) { struct inode *inode = filp->f_dentry->d_inode; struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode); @@ -194,6 +194,7 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) int rsize = 0; int result = 0; int total = 0; + int n; dprintk(DEBUG_VFS, "\n"); @@ -216,10 +217,15 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) } else *offset += result; - /* XXX - extra copy */ - memcpy(buffer, fcall->params.rread.data, result); + n = copy_to_user(data, fcall->params.rread.data, result); + if (n) { + dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n); + kfree(fcall); + return -EFAULT; + } + count -= result; - buffer += result; + data += result; total += result; kfree(fcall); @@ -232,42 +238,7 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) } /** - * v9fs_file_read - read from a file - * @filep: file pointer to read - * @data: data buffer to read data into - * @count: size of buffer - * @offset: offset at which to read data - * - */ - -static ssize_t -v9fs_file_read(struct file *filp, char __user * data, size_t count, - loff_t * offset) -{ - int retval = -1; - int ret = 0; - char *buffer; - - buffer = kmalloc(count, GFP_KERNEL); - if (!buffer) - return -ENOMEM; - - retval = v9fs_read(filp, buffer, count, offset); - if (retval > 0) { - if ((ret = copy_to_user(data, buffer, retval)) != 0) { - dprintk(DEBUG_ERROR, "Problem copying to user %d\n", - ret); - retval = ret; - } - } - - kfree(buffer); - - return retval; -} - -/** - * v9fs_write - write to a file + * v9fs_file_write - write to a file * @filep: file pointer to write * @data: data buffer to write data from * @count: size of buffer @@ -276,7 +247,8 @@ v9fs_file_read(struct file *filp, char __user * data, size_t count, */ static ssize_t -v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset) +v9fs_file_write(struct file *filp, const char __user * data, + size_t count, loff_t * offset) { struct inode *inode = filp->f_dentry->d_inode; struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode); @@ -286,30 +258,42 @@ v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset) int result = -EIO; int rsize = 0; int total = 0; + char *buf; - dprintk(DEBUG_VFS, "data %p count %d offset %x\n", buffer, (int)count, + dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count, (int)*offset); rsize = v9ses->maxdata - V9FS_IOHDRSZ; if (v9fid->iounit != 0 && rsize > v9fid->iounit) rsize = v9fid->iounit; - dump_data(buffer, count); + buf = kmalloc(v9ses->maxdata - V9FS_IOHDRSZ, GFP_KERNEL); + if (!buf) + return -ENOMEM; do { if (count < rsize) rsize = count; - result = - v9fs_t_write(v9ses, fid, *offset, rsize, buffer, &fcall); + result = copy_from_user(buf, data, rsize); + if (result) { + dprintk(DEBUG_ERROR, "Problem copying from user\n"); + kfree(buf); + return -EFAULT; + } + + dump_data(buf, rsize); + result = v9fs_t_write(v9ses, fid, *offset, rsize, buf, &fcall); if (result < 0) { eprintk(KERN_ERR, "error while writing: %s(%d)\n", FCALL_ERROR(fcall), result); kfree(fcall); + kfree(buf); return result; } else *offset += result; kfree(fcall); + fcall = NULL; if (result != rsize) { eprintk(KERN_ERR, @@ -319,46 +303,14 @@ v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset) } count -= result; - buffer += result; + data += result; total += result; } while (count); + kfree(buf); return total; } -/** - * v9fs_file_write - write to a file - * @filep: file pointer to write - * @data: data buffer to write data from - * @count: size of buffer - * @offset: offset at which to write data - * - */ - -static ssize_t -v9fs_file_write(struct file *filp, const char __user * data, - size_t count, loff_t * offset) -{ - int ret = -1; - char *buffer; - - buffer = kmalloc(count, GFP_KERNEL); - if (buffer == NULL) - return -ENOMEM; - - ret = copy_from_user(buffer, data, count); - if (ret) { - dprintk(DEBUG_ERROR, "Problem copying from user\n"); - ret = -EFAULT; - } else { - ret = v9fs_write(filp, buffer, count, offset); - } - - kfree(buffer); - - return ret; -} - struct file_operations v9fs_file_operations = { .llseek = generic_file_llseek, .read = v9fs_file_read,