u-boot: remove driver lookup loop from env_save()

When called with ENVOP_SAVE, env_get_location() only returns the gd->env_load_location variable without actually checking for the environment location and priority.

This behaviour causes env_save() to fall into an infinite loop when the low-level drv->save() call fails.

The env_save() function should not loop through the environment location list but it should save the environment into the location stored in gd->env_load_location by the last env_load() call.

Signed-off-by Nicholas Faustini <[email protected]>

---

Changes in v3:
- Add comment when env_load() fails and the env location is restored
- Introduce env_load_prio into gd struct. It stores the current priority of the environment location. Refactor of env_get_location() which acts the same on all the 'env_operation'

Changes in v2:
- Restore gd->env_load_location to the highest priority location when env_load() fails

  env/env.c                         | 35 +++++++++++++++++------------------
  include/asm-generic/global_data.h |  1 +
  2 files changed, 18 insertions(+), 18 deletions(-)

env/env.c +0 -11

index 5c0842a..ba13ba8 100644
@@ -119,21 +119,13 @@ static void env_set_inited(enum env_location location)
   */
  __weak enum env_location env_get_location(enum env_operation op, int prio)
  {
-	switch (op) {
-	case ENVOP_GET_CHAR:
-	case ENVOP_INIT:
-	case ENVOP_LOAD:
-		if (prio >= ARRAY_SIZE(env_locations))
-			return ENVL_UNKNOWN;
-
-		gd->env_load_location = env_locations[prio];
-		return gd->env_load_location;
-
-	case ENVOP_SAVE:

env/env.c +11 -4

  }
 
 

@@ -205,22 +197,29 @@ int env_load(void)
  			return 0;
  	}
 
+	/*
+	 * In case of invalid environment, we set the 'default' env location
+	 * to the highest priority. In this way, next calls to env_save()
+	 * will restore the environment at the right place.
+	 */
+	env_get_location(ENVOP_LOAD, 0);
+
  	return -ENODEV;
  }
 
  int env_save(void)
  {
  	struct env_driver *drv;
-	int prio;
 
-	for (prio = 0; (drv = env_driver_lookup(ENVOP_SAVE, prio)); prio++) {
+	drv = env_driver_lookup(ENVOP_SAVE, gd->env_load_prio);
+	if (drv) {
  		int ret;
 
  		if (!drv->save)
-			continue;
+			return -ENODEV;
 
  		if (!env_has_inited(drv->location))
-			continue;
+			return -ENODEV;
 
  		printf("Saving Environment to %s... ", drv->name);
  		ret = drv->save();

include/asm-generic/global_data.h +1 -0

index 2d451f8..319810a 100644
@@ -51,6 +51,7 @@ typedef struct global_data {
  	unsigned long env_valid;	/* Environment valid? enum env_valid */
  	unsigned long env_has_init;	/* Bitmask of boolean of struct env_location offsets */
  	int env_load_location;
+	int env_load_prio;
 
  	unsigned long ram_top;		/* Top address of RAM used by U-Boot */
  	unsigned long relocaddr;	/* Start address of U-Boot in RAM */

Quoted 62 lines · Nicholas Faustini

When called with ENVOP_SAVE, env_get_location() only returns the gd->env_load_location variable without actually checking for the environment location and priority.

This behaviour causes env_save() to fall into an infinite loop when the low-level drv->save() call fails.

The env_save() function should not loop through the environment location list but it should save the environment into the location stored in gd->env_load_location by the last env_load() call.

Signed-off-by Nicholas Faustini <[email protected]>

---

Changes in v3:
- Add comment when env_load() fails and the env location is restored
- Introduce env_load_prio into gd struct. It stores the current priority of the environment location. Refactor of env_get_location()
   which acts the same on all the 'env_operation'

Changes in v2:
- Restore gd->env_load_location to the highest priority location when
   env_load() fails

  env/env.c                         | 35 +++++++++++++++++---------
---------
  include/asm-generic/global_data.h |  1 +

  2 files changed, 18 insertions(+), 18 deletions(-)

env/env.c +5 -13

index 5c0842a..ba13ba8 100644
@@ -119,21 +119,13 @@ static void env_set_inited(enum env_location
 location)
    */
   __weak enum env_location env_get_location(enum env_operation op,
 int prio)
   {
-	switch (op) {
-	case ENVOP_GET_CHAR:
-	case ENVOP_INIT:
-	case ENVOP_LOAD:
-		if (prio >= ARRAY_SIZE(env_locations))
-			return ENVL_UNKNOWN;
-
-		gd->env_load_location = env_locations[prio];
-		return gd->env_load_location;
-
-	case ENVOP_SAVE:
-		return gd->env_load_location;
-	}
+	if (prio >= ARRAY_SIZE(env_locations))
+		return ENVL_UNKNOWN;
+
+	gd->env_load_location = env_locations[prio];
+	gd->env_load_prio = prio;

env/env.c

Quoted 2 lines

env/env.c +1 -1

-	return ENVL_UNKNOWN;
+	return gd->env_load_location;

Ehrm, I just saw gd->env_load_location is now unused... Other than that:

Reviewed-by Simon Goldschmidt <[email protected]>

Quoted 61 lines

  }

env/env.c +0 -0

@@ -205,22 +197,29 @@ int env_load(void)
   			return 0;
   	}

env/env.c +2 -0

+	/*
+	 * In case of invalid environment, we set the 'default'

env location

env/env.c +1 -0

+	 * to the highest priority. In this way, next calls to

env_save()

env/env.c +4 -0

+	 * will restore the environment at the right place.
+	 */
+	env_get_location(ENVOP_LOAD, 0);
+

   return -ENODEV;
  }

  int env_save(void)
  {
   struct env_driver *drv;

env/env.c +0 -1

-	int prio;

env/env.c +0 -1

-	for (prio = 0; (drv = env_driver_lookup(ENVOP_SAVE,

prio)); prio++) {

env/env.c +2 -0

+	drv = env_driver_lookup(ENVOP_SAVE, gd->env_load_prio);
+	if (drv) {

   int ret;

   if (!drv->save)

env/env.c +1 -1

-			continue;
+			return -ENODEV;

   if (!env_has_inited(drv->location))

env/env.c +1 -1

-			continue;
+			return -ENODEV;

   printf("Saving Environment to %s... ", drv-

Quoted 1 line

name);

   ret = drv->save();

include/asm- renamed from include/asm-generic/global_data.h +0 -0

generic/global_data.h
index 2d451f8..319810a 100644

include/asm-generic/global_data.h +0 -0

@@ -51,6 +51,7 @@ typedef struct global_data {

   unsigned long env_valid; /* Environment valid?
enum env_valid */
   unsigned long env_has_init; /* Bitmask of boolean
of struct env_location offsets */
   int env_load_location;

include/asm-generic/global_data.h +1 -0

+	int env_load_prio;

   unsigned long ram_top; /* Top address of
RAM used by U-Boot */
   unsigned long relocaddr; /* Start address of U-
Boot in RAM */