[PATCH] fix erasing/protecting flashes with unspecified size

[Sascha Hauer]

fixes: 81737c1 mtd: Fix erasing of devices >4GiB

Several places erased a complete flash partition passing ~0 as count to
erase(). With the above commit count to erase was changed from an unsigned
type to a signed type, so the (count > f->size - offset) check in
erase() no longer triggers and the ~0 count is no longer adjusted to the whole
device size. Among other things this results in saveenv failures on NOR
flashes.
This patch fixes this by introducing an explicit macro for erasing the
whole device which is tested for in erase(). All other negative values
are rejected.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Reported-by: Giorgio <giorgio.nicole at arcor.de>
---
 arch/arm/mach-omap/am33xx_bbu_nand.c    | 2 +-
 arch/arm/mach-omap/am33xx_bbu_spi_mlo.c | 2 +-
 commands/flash.c                        | 2 +-
 common/environment.c                    | 3 ++-
 drivers/usb/gadget/dfu.c                | 4 ++--
 drivers/usb/gadget/f_fastboot.c         | 2 +-
 fs/fs.c                                 | 4 +++-
 include/fs.h                            | 1 +
 8 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mach-omap/am33xx_bbu_nand.c b/arch/arm/mach-omap/am33xx_bbu_nand.c
index ee767d3..25f0e79 100644
--- a/arch/arm/mach-omap/am33xx_bbu_nand.c
+++ b/arch/arm/mach-omap/am33xx_bbu_nand.c
@@ -40,7 +40,7 @@ static int write_image(const char *devfile, const void *image, size_t size)
 		return fd;
 	}
 
-	ret = erase(fd, ~0, 0);
+	ret = erase(fd, ERASE_SIZE_ALL, 0);
 	if (ret < 0) {
 		pr_err("could not erase %s: %s\n", devfile,
 			errno_str());
diff --git a/arch/arm/mach-omap/am33xx_bbu_spi_mlo.c b/arch/arm/mach-omap/am33xx_bbu_spi_mlo.c
index 702bb9a..69a73ff 100644
--- a/arch/arm/mach-omap/am33xx_bbu_spi_mlo.c
+++ b/arch/arm/mach-omap/am33xx_bbu_spi_mlo.c
@@ -70,7 +70,7 @@ static int spi_nor_mlo_handler(struct bbu_handler *handler,
 		goto out;
 	}
 
-	ret = erase(dstfd, ~0, 0);
+	ret = erase(dstfd, ERASE_SIZE_ALL, 0);
 	if (ret < 0) {
 		printf("could not erase %s: %s", data->devicefile, errno_str());
 		goto out1;
diff --git a/commands/flash.c b/commands/flash.c
index 99d3cb7..d881b4d 100644
--- a/commands/flash.c
+++ b/commands/flash.c
@@ -32,7 +32,7 @@ static int do_flerase(int argc, char *argv[])
 	int fd;
 	char *filename = NULL;
 	struct stat s;
-	loff_t start = 0, size = ~0;
+	loff_t start = 0, size;
 	int ret = 0;
 
 	if (argc == 1)
diff --git a/common/environment.c b/common/environment.c
index 9cf44a0..be102db 100644
--- a/common/environment.c
+++ b/common/environment.c
@@ -88,6 +88,7 @@ static int do_compare_file(const char *filename, const char *base)
 }
 
 #else
+#define ERASE_SIZE_ALL 0
 static inline int protect(int fd, size_t count, unsigned long offset, int prot)
 {
 	return 0;
@@ -329,7 +330,7 @@ int envfs_save(const char *filename, const char *dirname, unsigned flags)
 		goto out;
 	}
 
-	ret = erase(envfd, ~0, 0);
+	ret = erase(envfd, ERASE_SIZE_ALL, 0);
 
 	/* ENOSYS and EOPNOTSUPP aren't errors here, many devices don't need it */
 	if (ret && errno != ENOSYS && errno != EOPNOTSUPP) {
diff --git a/drivers/usb/gadget/dfu.c b/drivers/usb/gadget/dfu.c
index 351b584..d7bf92c 100644
--- a/drivers/usb/gadget/dfu.c
+++ b/drivers/usb/gadget/dfu.c
@@ -359,7 +359,7 @@ static int handle_dnload(struct usb_function *f, const struct usb_ctrlrequest *c
 				ret = -EINVAL;
 				goto err_out;
 			}
-			ret = erase(fd, ~0, 0);
+			ret = erase(fd, ERASE_SIZE_ALL, 0);
 			close(fd);
 			if (ret && ret != -ENOSYS) {
 				perror("erase");
@@ -479,7 +479,7 @@ static int dfu_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 				goto out;
 			}
 
-			ret = erase(dfufd, ~0, 0);
+			ret = erase(dfufd, ERASE_SIZE_ALL, 0);
 			if (ret && ret != -ENOSYS) {
 				dfu->dfu_status = DFU_STATUS_errERASE;
 				perror("erase");
diff --git a/drivers/usb/gadget/f_fastboot.c b/drivers/usb/gadget/f_fastboot.c
index 0df08c9..aaf7849 100644
--- a/drivers/usb/gadget/f_fastboot.c
+++ b/drivers/usb/gadget/f_fastboot.c
@@ -784,7 +784,7 @@ static void cb_erase(struct usb_ep *ep, struct usb_request *req, const char *cmd
 	if (fd < 0)
 		fastboot_tx_print(f_fb, "FAIL%s", strerror(-fd));
 
-	ret = erase(fd, ~0, 0);
+	ret = erase(fd, ERASE_SIZE_ALL, 0);
 
 	close(fd);
 
diff --git a/fs/fs.c b/fs/fs.c
index 440adae..966abe9 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -935,8 +935,10 @@ int erase(int fd, loff_t count, loff_t offset)
 	f = &files[fd];
 	if (offset >= f->size)
 		return 0;
-	if (count > f->size - offset)
+	if (count == ERASE_SIZE_ALL || count > f->size - offset)
 		count = f->size - offset;
+	if (count < 0)
+		return -EINVAL;
 
 	fsdrv = f->fsdev->driver;
 	if (fsdrv->erase)
diff --git a/include/fs.h b/include/fs.h
index b9d1e6e..943ba55 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -147,6 +147,7 @@ int umount(const char *pathname);
 int umount_by_cdev(struct cdev *cdev);
 
 /* not-so-standard functions */
+#define ERASE_SIZE_ALL	((loff_t) - 1)
 int erase(int fd, loff_t count, loff_t offset);
 int protect(int fd, size_t count, loff_t offset, int prot);
 int protect_file(const char *file, int prot);
-- 
2.7.0