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scst_vdisk: Rework vdisk_set_wt() and vcdrom_change()

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This patch breaks the transactional properties of these functions but
makes it easier to port these functions to Linux kernel v5.10.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@9315 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Bart Van Assche
2021-01-03 02:48:04 +00:00
parent 6b420cfb32
commit 1c3d35bdab
1 changed files with 17 additions and 45 deletions
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62
scst/src/dev_handlers/scst_vdisk.c
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@@ -1417,6 +1417,16 @@ static void vdisk_close_fd(struct scst_vdisk_dev *virt_dev)
}
}
static int vdisk_reopen_fd(struct scst_vdisk_dev *virt_dev, bool read_only)
{
/*
* To do: make this function transactional. That means that it either
* succeeds or does not modify the state of @virt_dev.
*/
vdisk_close_fd(virt_dev);
return vdisk_open_fd(virt_dev, read_only);
}
/* Invoked with scst_mutex held, so no further locking is necessary here. */
static int vdisk_attach_tgt(struct scst_tgt_dev *tgt_dev)
{
@@ -4541,7 +4551,6 @@ out_not_sup:
static int vdisk_set_wt(struct scst_vdisk_dev *virt_dev, int wt, bool read_only)
{
int res = 0;
struct file *fd, *dif_fd = NULL;
bool old_wt = virt_dev->wt_flag;
TRACE_ENTRY();
@@ -4553,42 +4562,20 @@ static int vdisk_set_wt(struct scst_vdisk_dev *virt_dev, int wt, bool read_only)
virt_dev->wt_flag = wt;
spin_unlock(&virt_dev->flags_lock);
if (virt_dev->fd == NULL)
goto out;
/*
* MODE SELECT is strictly serialized command, so it's safe here
* to reopen fd.
* MODE SELECT is a strictly serialized command so it's safe to reopen
* the fd.
*/
fd = vdev_open_fd(virt_dev, virt_dev->filename, read_only);
if (IS_ERR(fd)) {
res = PTR_ERR(fd);
goto out_err;
if (virt_dev->fd) {
res = vdisk_reopen_fd(virt_dev, read_only);
if (res < 0)
goto out_err;
}
if (virt_dev->dif_filename != NULL) {
dif_fd = vdev_open_fd(virt_dev, virt_dev->dif_filename, read_only);
if (IS_ERR(dif_fd)) {
res = PTR_ERR(dif_fd);
goto out_err_close_fd;
}
}
filp_close(virt_dev->fd, NULL);
if (virt_dev->dif_fd)
filp_close(virt_dev->dif_fd, NULL);
virt_dev->fd = fd;
virt_dev->dif_fd = dif_fd;
out:
TRACE_EXIT_RES(res);
return res;
out_err_close_fd:
filp_close(fd, NULL);
out_err:
spin_lock(&virt_dev->flags_lock);
virt_dev->wt_flag = old_wt;
@@ -7668,8 +7655,6 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev, char *buffer)
loff_t err;
char *old_fn, *p;
bool old_empty;
struct file *old_fd;
struct file *old_dif_fd;
const char *filename = NULL;
int length = strlen(buffer);
int res = 0;
@@ -7680,8 +7665,6 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev, char *buffer)
virt_dev->name, virt_dev->cdrom_empty, virt_dev->fd,
virt_dev->dif_fd, virt_dev->filename);
sBUG_ON(virt_dev->dif_fd); /* DIF is not supported for CDROMs */
if (virt_dev->prevent_allow_medium_removal) {
PRINT_ERROR("Prevent medium removal for "
"virtual device with name %s", virt_dev->name);
@@ -7710,8 +7693,6 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev, char *buffer)
mutex_lock(&scst_mutex);
old_empty = virt_dev->cdrom_empty;
old_fd = virt_dev->fd;
old_dif_fd = virt_dev->dif_fd;
old_fn = virt_dev->filename;
if (*filename == '\0') {
@@ -7739,18 +7720,10 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev, char *buffer)
if (res != 0)
goto out_free_fn;
if (virt_dev->fd == NULL) {
res = vdisk_open_fd(virt_dev, true);
res = vdisk_reopen_fd(virt_dev, true);
if (res != 0)
goto out_free_fn;
sBUG_ON(!virt_dev->fd);
TRACE_DBG("Closing old_fd %p", old_fd);
if (old_fd != NULL)
filp_close(old_fd, NULL);
if (old_dif_fd != NULL)
filp_close(old_dif_fd, NULL);
old_fd = NULL;
old_dif_fd = NULL;
}
} else {
err = 0;
@@ -7793,7 +7766,6 @@ out:
return res;
out_free_fn:
virt_dev->fd = old_fd;
kfree(virt_dev->filename);
virt_dev->filename = old_fn;