Messages in this thread Patch in this message | | | From | Davide Libenzi <> | Date | Wed, 06 Jun 2007 15:30:31 -0700 | Subject | [patch 4/8] fdmap v2 - add a new O_NONSEQFD flag to sys_open |
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This patch introduces a new O_NONSEQFD flag for the sys_open() system call. Using such flag, the caller can ask the kernel to allocate the file descriptor inside the non-sequential area.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
- Davide
Index: linux-2.6.mod/fs/open.c =================================================================== --- linux-2.6.mod.orig/fs/open.c 2007-06-06 12:48:03.000000000 -0700 +++ linux-2.6.mod/fs/open.c 2007-06-06 12:48:37.000000000 -0700 @@ -978,6 +978,23 @@ return FDMAP_NONSEQ_BASE + (rndb & ((1U << FDMAP_RANDOM_BITS) - 1)); } +/** + * allocate_fd - Allocates a new file descriptor + * + * @flags: [in] Flags to control the allocation type and the new descriptor + * characteristics + * + * Returns the newly allocated file descriptor, or a negative value in + * case of error. + */ +int allocate_fd(unsigned long flags) +{ + if (flags & O_NONSEQFD) + return alloc_nonseq_fd(current->files, flags); + else + return get_unused_fd(); +} + /* * Install a file pointer in the fd array. * @@ -1011,7 +1028,7 @@ int fd = PTR_ERR(tmp); if (!IS_ERR(tmp)) { - fd = get_unused_fd(); + fd = allocate_fd((unsigned int) flags); if (fd >= 0) { struct file *f = do_filp_open(dfd, tmp, flags, mode); if (IS_ERR(f)) { Index: linux-2.6.mod/include/asm-generic/fcntl.h =================================================================== --- linux-2.6.mod.orig/include/asm-generic/fcntl.h 2007-06-06 12:38:27.000000000 -0700 +++ linux-2.6.mod/include/asm-generic/fcntl.h 2007-06-06 12:48:37.000000000 -0700 @@ -48,6 +48,9 @@ #ifndef O_NOATIME #define O_NOATIME 01000000 #endif +#ifndef O_NONSEQFD +#define O_NONSEQFD 02000000 +#endif #ifndef O_NDELAY #define O_NDELAY O_NONBLOCK #endif Index: linux-2.6.mod/include/linux/file.h =================================================================== --- linux-2.6.mod.orig/include/linux/file.h 2007-06-06 12:48:28.000000000 -0700 +++ linux-2.6.mod/include/linux/file.h 2007-06-06 12:48:37.000000000 -0700 @@ -85,6 +85,7 @@ extern int __alloc_nonseq_fd(struct files_struct *files, unsigned long flags); extern int alloc_nonseq_fd(struct files_struct *files, unsigned long flags); extern unsigned int gen_nonseqfd_base(void); +extern int allocate_fd(unsigned long flags); /** * nonseq_files_fdmap - Must be called with @files->file_lock held. It forces - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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