[PATCH 18/18] libio: Add hold/drop iop reference
Sebastian Huber
sebastian.huber at embedded-brains.de
Wed Sep 13 13:39:51 UTC 2017
Update #3132.
---
cpukit/libcsupport/include/rtems/libio.h | 8 ++--
cpukit/libcsupport/include/rtems/libio_.h | 71 +++++++++++++++++++++----------
cpukit/libcsupport/src/close.c | 41 ++++++++++++++++--
cpukit/libcsupport/src/fchdir.c | 1 +
cpukit/libcsupport/src/fchmod.c | 2 +
cpukit/libcsupport/src/fchown.c | 2 +
cpukit/libcsupport/src/fcntl.c | 2 +
cpukit/libcsupport/src/fdatasync.c | 5 ++-
cpukit/libcsupport/src/fpathconf.c | 4 +-
cpukit/libcsupport/src/fstat.c | 5 ++-
cpukit/libcsupport/src/fsync.c | 5 ++-
cpukit/libcsupport/src/ftruncate.c | 1 +
cpukit/libcsupport/src/ioctl.c | 1 +
cpukit/libcsupport/src/libio.c | 12 +++---
cpukit/libcsupport/src/lseek.c | 5 ++-
cpukit/libcsupport/src/read.c | 5 ++-
cpukit/libcsupport/src/write.c | 5 ++-
17 files changed, 132 insertions(+), 43 deletions(-)
diff --git a/cpukit/libcsupport/include/rtems/libio.h b/cpukit/libcsupport/include/rtems/libio.h
index 2a67496800..804929915a 100644
--- a/cpukit/libcsupport/include/rtems/libio.h
+++ b/cpukit/libcsupport/include/rtems/libio.h
@@ -37,6 +37,7 @@
#include <rtems.h>
#include <rtems/fs.h>
#include <rtems/chain.h>
+#include <rtems/score/atomic.h>
#ifdef __cplusplus
extern "C" {
@@ -1319,7 +1320,7 @@ extern const rtems_filesystem_limits_and_options_t
struct rtems_libio_tt {
rtems_driver_name_t *driver;
off_t offset; /* current offset into file */
- uint32_t flags;
+ Atomic_Uint flags;
rtems_filesystem_location_info_t pathinfo;
uint32_t data0; /* private to "driver" */
void *data1; /* ... */
@@ -1371,12 +1372,13 @@ typedef struct {
#define LIBIO_FLAGS_APPEND 0x0200U /* all writes append */
#define LIBIO_FLAGS_CLOSE_ON_EXEC 0x0800U /* close on process exec() */
#define LIBIO_FLAGS_READ_WRITE (LIBIO_FLAGS_READ | LIBIO_FLAGS_WRITE)
+#define LIBIO_FLAGS_REFERENCE_INC 0x1000U
/** @} */
-static inline uint32_t rtems_libio_iop_flags( const rtems_libio_t *iop )
+static inline unsigned int rtems_libio_iop_flags( const rtems_libio_t *iop )
{
- return iop->flags;
+ return _Atomic_Load_uint( &iop->flags, ATOMIC_ORDER_RELAXED );
}
/**
diff --git a/cpukit/libcsupport/include/rtems/libio_.h b/cpukit/libcsupport/include/rtems/libio_.h
index 0207a5c004..778499968e 100644
--- a/cpukit/libcsupport/include/rtems/libio_.h
+++ b/cpukit/libcsupport/include/rtems/libio_.h
@@ -97,16 +97,12 @@ extern rtems_filesystem_global_location_t rtems_filesystem_global_location_null;
*
* @return The previous flags.
*/
-static inline uint32_t rtems_libio_iop_flags_set(
+static inline unsigned int rtems_libio_iop_flags_set(
rtems_libio_t *iop,
- uint32_t set
+ unsigned int set
)
{
- uint32_t flags;
-
- flags = iop->flags;
- iop->flags = flags | set;
- return flags;
+ return _Atomic_Fetch_or_uint( &iop->flags, set, ATOMIC_ORDER_RELAXED );
}
/**
@@ -117,16 +113,12 @@ static inline uint32_t rtems_libio_iop_flags_set(
*
* @return The previous flags.
*/
-static inline uint32_t rtems_libio_iop_flags_clear(
+static inline unsigned int rtems_libio_iop_flags_clear(
rtems_libio_t *iop,
- uint32_t clear
+ unsigned int clear
)
{
- uint32_t flags;
-
- flags = iop->flags;
- iop->flags = flags & ~clear;
- return flags;
+ return _Atomic_Fetch_and_uint( &iop->flags, ~clear, ATOMIC_ORDER_RELAXED );
}
/**
@@ -143,6 +135,36 @@ static inline rtems_libio_t *rtems_libio_iop( int fd )
return &rtems_libio_iops[ fd ];
}
+/**
+ * @brief Holds a refernece to the iop.
+ *
+ * @param[in] iop The iop.
+ *
+ * @return The flags corresponding to the specified iop.
+ */
+static inline unsigned int rtems_libio_iop_hold( rtems_libio_t *iop )
+{
+ return _Atomic_Fetch_add_uint(
+ &iop->flags,
+ LIBIO_FLAGS_REFERENCE_INC,
+ ATOMIC_ORDER_ACQUIRE
+ );
+}
+
+/**
+ * @brief Drops a refernece to the iop.
+ *
+ * @param[in] iop The iop.
+ */
+static inline void rtems_libio_iop_drop( rtems_libio_t *iop )
+{
+ _Atomic_Fetch_sub_uint(
+ &iop->flags,
+ LIBIO_FLAGS_REFERENCE_INC,
+ ATOMIC_ORDER_RELEASE
+ );
+}
+
/*
* rtems_libio_iop_to_descriptor
*
@@ -174,13 +196,14 @@ static inline rtems_libio_t *rtems_libio_iop( int fd )
*/
#define LIBIO_GET_IOP( _fd, _iop ) \
do { \
- uint32_t _flags; \
+ unsigned int _flags; \
if ( (uint32_t) ( _fd ) >= rtems_libio_number_iops ) { \
rtems_set_errno_and_return_minus_one( EBADF ); \
} \
_iop = rtems_libio_iop( _fd ); \
- _flags = _iop->flags; \
+ _flags = rtems_libio_iop_hold( _iop ); \
if ( ( _flags & LIBIO_FLAGS_OPEN ) == 0 ) { \
+ rtems_libio_iop_drop( _iop ); \
rtems_set_errno_and_return_minus_one( EBADF ); \
} \
} while ( 0 )
@@ -193,16 +216,17 @@ static inline rtems_libio_t *rtems_libio_iop( int fd )
*/
#define LIBIO_GET_IOP_WITH_ACCESS( _fd, _iop, _access_flags, _access_error ) \
do { \
- uint32_t _flags; \
- uint32_t _mandatory; \
+ unsigned int _flags; \
+ unsigned int _mandatory; \
if ( (uint32_t) ( _fd ) >= rtems_libio_number_iops ) { \
rtems_set_errno_and_return_minus_one( EBADF ); \
} \
_iop = rtems_libio_iop( _fd ); \
- _flags = _iop->flags; \
+ _flags = rtems_libio_iop_hold( _iop ); \
_mandatory = LIBIO_FLAGS_OPEN | ( _access_flags ); \
if ( ( _flags & _mandatory ) != _mandatory ) { \
int _error; \
+ rtems_libio_iop_drop( _iop ); \
if ( ( _flags & LIBIO_FLAGS_OPEN ) == 0 ) { \
_error = EBADF; \
} else { \
@@ -334,17 +358,17 @@ static inline void rtems_filesystem_instance_unlock(
* This routine searches the IOP Table for an unused entry. If it
* finds one, it returns it. Otherwise, it returns NULL.
*/
-rtems_libio_t *rtems_libio_allocate(uint32_t flags);
+rtems_libio_t *rtems_libio_allocate(unsigned int flags);
/**
* Convert UNIX fnctl(2) flags to ones that RTEMS drivers understand
*/
-uint32_t rtems_libio_fcntl_flags( int fcntl_flags );
+unsigned int rtems_libio_fcntl_flags( int fcntl_flags );
/**
* Convert RTEMS internal flags to UNIX fnctl(2) flags
*/
-int rtems_libio_to_fcntl_flags( uint32_t flags );
+int rtems_libio_to_fcntl_flags( unsigned int flags );
/**
* This routine frees the resources associated with an IOP (file descriptor)
@@ -914,7 +938,7 @@ static inline ssize_t rtems_libio_iovec_eval(
int fd,
const struct iovec *iov,
int iovcnt,
- uint32_t flags,
+ unsigned int flags,
rtems_libio_iovec_adapter adapter
)
{
@@ -960,6 +984,7 @@ static inline ssize_t rtems_libio_iovec_eval(
total = ( *adapter )( iop, iov, iovcnt, total );
}
+ rtems_libio_iop_drop( iop );
return total;
}
diff --git a/cpukit/libcsupport/src/close.c b/cpukit/libcsupport/src/close.c
index 7eaeb64fea..d478e231c6 100644
--- a/cpukit/libcsupport/src/close.c
+++ b/cpukit/libcsupport/src/close.c
@@ -24,12 +24,45 @@ int close(
int fd
)
{
- rtems_libio_t *iop;
- int rc;
+ rtems_libio_t *iop;
+ unsigned int flags;
+ int rc;
- LIBIO_GET_IOP( fd, iop );
+ if ( (uint32_t) fd >= rtems_libio_number_iops ) {
+ rtems_set_errno_and_return_minus_one( EBADF );
+ }
- rtems_libio_iop_flags_clear( iop, LIBIO_FLAGS_OPEN );
+ iop = rtems_libio_iop( fd );
+ flags = rtems_libio_iop_flags( iop );
+
+ while ( true ) {
+ unsigned int desired;
+ bool success;
+
+ if ( ( flags & LIBIO_FLAGS_OPEN ) == 0 ) {
+ rtems_set_errno_and_return_minus_one( EBADF );
+ }
+
+ /* The expected flags */
+ flags &= LIBIO_FLAGS_REFERENCE_INC - 1U;
+
+ desired = flags & ~LIBIO_FLAGS_OPEN;
+ success = _Atomic_Compare_exchange_uint(
+ &iop->flags,
+ &flags,
+ desired,
+ ATOMIC_ORDER_ACQ_REL,
+ ATOMIC_ORDER_RELAXED
+ );
+
+ if ( success ) {
+ break;
+ }
+
+ if ( ( flags & ~( LIBIO_FLAGS_REFERENCE_INC - 1U ) ) != 0 ) {
+ rtems_set_errno_and_return_minus_one( EBUSY );
+ }
+ }
rc = (*iop->pathinfo.handlers->close_h)( iop );
diff --git a/cpukit/libcsupport/src/fchdir.c b/cpukit/libcsupport/src/fchdir.c
index ece73ab3ec..df37458ead 100644
--- a/cpukit/libcsupport/src/fchdir.c
+++ b/cpukit/libcsupport/src/fchdir.c
@@ -59,6 +59,7 @@ int fchdir( int fd )
}
}
rtems_filesystem_instance_unlock( &iop->pathinfo );
+ rtems_libio_iop_drop( iop );
if ( rv == 0 ) {
rv = rtems_filesystem_chdir( &loc );
diff --git a/cpukit/libcsupport/src/fchmod.c b/cpukit/libcsupport/src/fchmod.c
index 126b015501..13e7fdd380 100644
--- a/cpukit/libcsupport/src/fchmod.c
+++ b/cpukit/libcsupport/src/fchmod.c
@@ -75,5 +75,7 @@ int fchmod( int fd, mode_t mode )
rtems_filesystem_instance_unlock( &iop->pathinfo );
+ rtems_libio_iop_drop( iop );
+
return rv;
}
diff --git a/cpukit/libcsupport/src/fchown.c b/cpukit/libcsupport/src/fchown.c
index bd787d89e3..8c3d9b2c6c 100644
--- a/cpukit/libcsupport/src/fchown.c
+++ b/cpukit/libcsupport/src/fchown.c
@@ -72,5 +72,7 @@ int fchown( int fd, uid_t owner, gid_t group )
rtems_filesystem_instance_unlock( &iop->pathinfo );
+ rtems_libio_iop_drop( iop );
+
return rv;
}
diff --git a/cpukit/libcsupport/src/fcntl.c b/cpukit/libcsupport/src/fcntl.c
index 4da1e3daa6..a6ef45b715 100644
--- a/cpukit/libcsupport/src/fcntl.c
+++ b/cpukit/libcsupport/src/fcntl.c
@@ -209,6 +209,8 @@ static int vfcntl(
ret = -1;
}
}
+
+ rtems_libio_iop_drop( iop );
return ret;
}
diff --git a/cpukit/libcsupport/src/fdatasync.c b/cpukit/libcsupport/src/fdatasync.c
index 14e66726e6..bf90957f0f 100644
--- a/cpukit/libcsupport/src/fdatasync.c
+++ b/cpukit/libcsupport/src/fdatasync.c
@@ -28,6 +28,7 @@ int fdatasync(
)
{
rtems_libio_t *iop;
+ int rv;
LIBIO_GET_IOP_WITH_ACCESS( fd, iop, LIBIO_FLAGS_WRITE, EBADF );
@@ -35,5 +36,7 @@ int fdatasync(
* Now process the fdatasync().
*/
- return (*iop->pathinfo.handlers->fdatasync_h)( iop );
+ rv = (*iop->pathinfo.handlers->fdatasync_h)( iop );
+ rtems_libio_iop_drop( iop );
+ return rv;
}
diff --git a/cpukit/libcsupport/src/fpathconf.c b/cpukit/libcsupport/src/fpathconf.c
index db323136c7..d08ac9c776 100644
--- a/cpukit/libcsupport/src/fpathconf.c
+++ b/cpukit/libcsupport/src/fpathconf.c
@@ -82,9 +82,11 @@ long fpathconf(
return_value = the_limits->posix_sync_io;
break;
default:
- rtems_set_errno_and_return_minus_one( EINVAL );
+ errno = EINVAL;
+ return_value = -1;
break;
}
+ rtems_libio_iop_drop( iop );
return return_value;
}
diff --git a/cpukit/libcsupport/src/fstat.c b/cpukit/libcsupport/src/fstat.c
index 4a10d166bd..3a1241a862 100644
--- a/cpukit/libcsupport/src/fstat.c
+++ b/cpukit/libcsupport/src/fstat.c
@@ -26,6 +26,7 @@ int fstat(
)
{
rtems_libio_t *iop;
+ int rv;
/*
* Check to see if we were passed a valid pointer.
@@ -44,7 +45,9 @@ int fstat(
*/
memset( sbuf, 0, sizeof(struct stat) );
- return (*iop->pathinfo.handlers->fstat_h)( &iop->pathinfo, sbuf );
+ rv = (*iop->pathinfo.handlers->fstat_h)( &iop->pathinfo, sbuf );
+ rtems_libio_iop_drop( iop );
+ return rv;
}
/*
diff --git a/cpukit/libcsupport/src/fsync.c b/cpukit/libcsupport/src/fsync.c
index 6332180721..428f82abd0 100644
--- a/cpukit/libcsupport/src/fsync.c
+++ b/cpukit/libcsupport/src/fsync.c
@@ -31,6 +31,7 @@ int fsync(
)
{
rtems_libio_t *iop;
+ int rv;
LIBIO_GET_IOP( fd, iop );
@@ -38,5 +39,7 @@ int fsync(
* Now process the fsync().
*/
- return (*iop->pathinfo.handlers->fsync_h)( iop );
+ rv = (*iop->pathinfo.handlers->fsync_h)( iop );
+ rtems_libio_iop_drop( iop );
+ return rv;
}
diff --git a/cpukit/libcsupport/src/ftruncate.c b/cpukit/libcsupport/src/ftruncate.c
index 401510b2ff..99a9c6b5ef 100644
--- a/cpukit/libcsupport/src/ftruncate.c
+++ b/cpukit/libcsupport/src/ftruncate.c
@@ -32,6 +32,7 @@ int ftruncate( int fd, off_t length )
LIBIO_GET_IOP_WITH_ACCESS( fd, iop, LIBIO_FLAGS_WRITE, EINVAL );
rv = (*iop->pathinfo.handlers->ftruncate_h)( iop, length );
+ rtems_libio_iop_drop( iop );
} else {
errno = EINVAL;
rv = -1;
diff --git a/cpukit/libcsupport/src/ioctl.c b/cpukit/libcsupport/src/ioctl.c
index 9fa7fa15a2..b2be524075 100644
--- a/cpukit/libcsupport/src/ioctl.c
+++ b/cpukit/libcsupport/src/ioctl.c
@@ -51,5 +51,6 @@ int ioctl(
rc = (*iop->pathinfo.handlers->ioctl_h)( iop, command, buffer );
va_end( ap );
+ rtems_libio_iop_drop( iop );
return rc;
}
diff --git a/cpukit/libcsupport/src/libio.c b/cpukit/libcsupport/src/libio.c
index ab8779aa12..61644f8c1f 100644
--- a/cpukit/libcsupport/src/libio.c
+++ b/cpukit/libcsupport/src/libio.c
@@ -58,16 +58,16 @@ static const rtems_assoc_t status_flags_assoc[] = {
{ 0, 0, 0 },
};
-uint32_t rtems_libio_fcntl_flags( int fcntl_flags )
+unsigned int rtems_libio_fcntl_flags( int fcntl_flags )
{
- uint32_t flags = 0;
+ unsigned int flags = 0;
uint32_t access_modes;
/*
* Access mode is a small integer
*/
- access_modes = (uint32_t) (fcntl_flags & O_ACCMODE);
+ access_modes = (unsigned int) (fcntl_flags & O_ACCMODE);
fcntl_flags &= ~O_ACCMODE;
flags = rtems_assoc_local_by_remote( access_modes_assoc, access_modes );
@@ -75,7 +75,7 @@ uint32_t rtems_libio_fcntl_flags( int fcntl_flags )
* Everything else is single bits
*/
- flags |= rtems_assoc_local_by_remote_bitfield(
+ flags |= (unsigned int ) rtems_assoc_local_by_remote_bitfield(
status_flags_assoc,
(uint32_t) fcntl_flags
);
@@ -83,7 +83,7 @@ uint32_t rtems_libio_fcntl_flags( int fcntl_flags )
return flags;
}
-int rtems_libio_to_fcntl_flags( uint32_t flags )
+int rtems_libio_to_fcntl_flags( unsigned int flags )
{
int fcntl_flags = 0;
@@ -106,7 +106,7 @@ int rtems_libio_to_fcntl_flags( uint32_t flags )
return fcntl_flags;
}
-rtems_libio_t *rtems_libio_allocate( uint32_t flags )
+rtems_libio_t *rtems_libio_allocate( unsigned int flags )
{
rtems_libio_t *iop = NULL;
diff --git a/cpukit/libcsupport/src/lseek.c b/cpukit/libcsupport/src/lseek.c
index 16271eba09..00307e3e0d 100644
--- a/cpukit/libcsupport/src/lseek.c
+++ b/cpukit/libcsupport/src/lseek.c
@@ -20,10 +20,13 @@
off_t lseek( int fd, off_t offset, int whence )
{
rtems_libio_t *iop;
+ off_t rv;
LIBIO_GET_IOP( fd, iop );
- return (*iop->pathinfo.handlers->lseek_h)( iop, offset, whence );
+ rv = (*iop->pathinfo.handlers->lseek_h)( iop, offset, whence );
+ rtems_libio_iop_drop( iop );
+ return rv;
}
/*
diff --git a/cpukit/libcsupport/src/read.c b/cpukit/libcsupport/src/read.c
index d55ff180ae..03c39120bb 100644
--- a/cpukit/libcsupport/src/read.c
+++ b/cpukit/libcsupport/src/read.c
@@ -31,6 +31,7 @@ ssize_t read(
)
{
rtems_libio_t *iop;
+ ssize_t n;
rtems_libio_check_buffer( buffer );
rtems_libio_check_count( count );
@@ -40,7 +41,9 @@ ssize_t read(
/*
* Now process the read().
*/
- return (*iop->pathinfo.handlers->read_h)( iop, buffer, count );
+ n = (*iop->pathinfo.handlers->read_h)( iop, buffer, count );
+ rtems_libio_iop_drop( iop );
+ return n;
}
#if defined(RTEMS_NEWLIB) && !defined(HAVE__READ_R)
diff --git a/cpukit/libcsupport/src/write.c b/cpukit/libcsupport/src/write.c
index f44962afd8..a90b291ed8 100644
--- a/cpukit/libcsupport/src/write.c
+++ b/cpukit/libcsupport/src/write.c
@@ -34,6 +34,7 @@ ssize_t write(
)
{
rtems_libio_t *iop;
+ ssize_t n;
rtems_libio_check_buffer( buffer );
rtems_libio_check_count( count );
@@ -43,5 +44,7 @@ ssize_t write(
/*
* Now process the write() request.
*/
- return (*iop->pathinfo.handlers->write_h)( iop, buffer, count );
+ n = (*iop->pathinfo.handlers->write_h)( iop, buffer, count );
+ rtems_libio_iop_drop( iop );
+ return n;
}
--
2.12.3
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