block: Make blk_{pread,pwrite}() return 0 on success

They currently return the value of their 'bytes' parameter on success.

Make them return 0 instead, for consistency with other I/O functions and
in preparation to implement them using generated_co_wrapper. This also
makes it clear that short reads/writes are not possible.

Signed-off-by: Alberto Faria <afaria@redhat.com>
Message-Id: <20220705161527.1054072-2-afaria@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

2 files changed, 11 insertions, 11 deletions

diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index d695f6a..8fd9f97 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -64,8 +64,8 @@ int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
     case I2C_START_RECV:
         DPRINTK("clear\n");
         if (ee->blk && ee->changed) {
-            int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0);
-            if (len != ee->rsize) {
+            int ret = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0);
+            if (ret < 0) {
                 ERR(TYPE_AT24C_EE
                         " : failed to write backing file\n");
             }
@@ -165,9 +165,9 @@ void at24c_eeprom_reset(DeviceState *state)
     memset(ee->mem, 0, ee->rsize);
 
     if (ee->blk) {
-        int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize);
+        int ret = blk_pread(ee->blk, 0, ee->mem, ee->rsize);
 
-        if (len != ee->rsize) {
+        if (ret < 0) {
             ERR(TYPE_AT24C_EE
                     " : Failed initial sync with backing file\n");
         }
diff --git a/hw/nvram/spapr_nvram.c b/hw/nvram/spapr_nvram.c
index 18b43be..59d2e7b 100644
--- a/hw/nvram/spapr_nvram.c
+++ b/hw/nvram/spapr_nvram.c
@@ -103,7 +103,7 @@ static void rtas_nvram_store(PowerPCCPU *cpu, SpaprMachineState *spapr,
 {
     SpaprNvram *nvram = spapr->nvram;
     hwaddr offset, buffer, len;
-    int alen;
+    int ret;
     void *membuf;
 
     if ((nargs != 3) || (nret != 2)) {
@@ -128,9 +128,9 @@ static void rtas_nvram_store(PowerPCCPU *cpu, SpaprMachineState *spapr,
 
     membuf = cpu_physical_memory_map(buffer, &len, false);
 
-    alen = len;
+    ret = 0;
     if (nvram->blk) {
-        alen = blk_pwrite(nvram->blk, offset, membuf, len, 0);
+        ret = blk_pwrite(nvram->blk, offset, membuf, len, 0);
     }
 
     assert(nvram->buf);
@@ -138,8 +138,8 @@ static void rtas_nvram_store(PowerPCCPU *cpu, SpaprMachineState *spapr,
 
     cpu_physical_memory_unmap(membuf, len, 0, len);
 
-    rtas_st(rets, 0, (alen < len) ? RTAS_OUT_HW_ERROR : RTAS_OUT_SUCCESS);
-    rtas_st(rets, 1, (alen < 0) ? 0 : alen);
+    rtas_st(rets, 0, (ret < 0) ? RTAS_OUT_HW_ERROR : RTAS_OUT_SUCCESS);
+    rtas_st(rets, 1, (ret < 0) ? 0 : len);
 }
 
 static void spapr_nvram_realize(SpaprVioDevice *dev, Error **errp)
@@ -179,9 +179,9 @@ static void spapr_nvram_realize(SpaprVioDevice *dev, Error **errp)
     }
 
     if (nvram->blk) {
-        int alen = blk_pread(nvram->blk, 0, nvram->buf, nvram->size);
+        ret = blk_pread(nvram->blk, 0, nvram->buf, nvram->size);
 
-        if (alen != nvram->size) {
+        if (ret < 0) {
             error_setg(errp, "can't read spapr-nvram contents");
             return;
         }