From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Diego Domingos <diegodo@br.ibm.com>

Date: Mon, 14 Dec 2020 17:24:02 +0100

Subject: [PATCH] ieee1275: Avoiding many unecessary open/close

Signed-off-by: Diego Domingos <diegodo@br.ibm.com>

---

 grub-core/disk/ieee1275/ofdisk.c | 63 ++++++++++++++++++++++------------------

 1 file changed, 34 insertions(+), 29 deletions(-)

diff --git a/grub-core/disk/ieee1275/ofdisk.c b/grub-core/disk/ieee1275/ofdisk.c

index d887d4b6eee..d0ee4ae9851 100644

--- a/grub-core/disk/ieee1275/ofdisk.c

+++ b/grub-core/disk/ieee1275/ofdisk.c

@@ -44,7 +44,7 @@ struct ofdisk_hash_ent

 };

 static grub_err_t

-grub_ofdisk_get_block_size (const char *device, grub_uint32_t *block_size,

+grub_ofdisk_get_block_size (grub_uint32_t *block_size,

 			    struct ofdisk_hash_ent *op);

 #define OFDISK_HASH_SZ	8

@@ -461,6 +461,7 @@ grub_ofdisk_open (const char *name, grub_disk_t disk)

   grub_ssize_t actual;

   grub_uint32_t block_size = 0;

   grub_err_t err;

+  struct ofdisk_hash_ent *op;

   if (grub_strncmp (name, "ieee1275/", sizeof ("ieee1275/") - 1) != 0)

       return grub_error (GRUB_ERR_UNKNOWN_DEVICE,

@@ -471,6 +472,34 @@ grub_ofdisk_open (const char *name, grub_disk_t disk)

   grub_dprintf ("disk", "Opening `%s'.\n", devpath);

+  op = ofdisk_hash_find (devpath);

+  if (!op)

+    op = ofdisk_hash_add (devpath, NULL);

+  if (!op)

+    {

+      grub_free (devpath);

+      return grub_errno;

+    }

+

+  /* Check if the call to open is the same to the last disk already opened */

+  if (last_devpath && !grub_strcmp(op->open_path,last_devpath))

+  {

+      goto finish;

+  }

+

+ /* If not, we need to close the previous disk and open the new one */

+  else {

+    if (last_ihandle){

+        grub_ieee1275_close (last_ihandle);

+    }

+    last_ihandle = 0;

+    last_devpath = NULL;

+

+    grub_ieee1275_open (op->open_path, &last_ihandle);

+    if (! last_ihandle)

+      return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "can't open device");

+  }

+

   if (grub_ieee1275_finddevice (devpath, &dev))

     {

       grub_free (devpath);

@@ -491,25 +520,18 @@ grub_ofdisk_open (const char *name, grub_disk_t disk)

       return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a block device");

     }

+

+  finish:

   /* XXX: There is no property to read the number of blocks.  There

      should be a property `#blocks', but it is not there.  Perhaps it

      is possible to use seek for this.  */

   disk->total_sectors = GRUB_DISK_SIZE_UNKNOWN;

   {

-    struct ofdisk_hash_ent *op;

-    op = ofdisk_hash_find (devpath);

-    if (!op)

-      op = ofdisk_hash_add (devpath, NULL);

-    if (!op)

-      {

-        grub_free (devpath);

-        return grub_errno;

-      }

     disk->id = (unsigned long) op;

     disk->data = op->open_path;

-    err = grub_ofdisk_get_block_size (devpath, &block_size, op);

+    err = grub_ofdisk_get_block_size (&block_size, op);

     if (err)

       {

         grub_free (devpath);

@@ -532,13 +554,6 @@ grub_ofdisk_open (const char *name, grub_disk_t disk)

 static void

 grub_ofdisk_close (grub_disk_t disk)

 {

-  if (disk->data == last_devpath)

-    {

-      if (last_ihandle)

-	grub_ieee1275_close (last_ihandle);

-      last_ihandle = 0;

-      last_devpath = NULL;

-    }

   disk->data = 0;

 }

@@ -685,7 +700,7 @@ grub_ofdisk_init (void)

 }

 static grub_err_t

-grub_ofdisk_get_block_size (const char *device, grub_uint32_t *block_size,

+grub_ofdisk_get_block_size (grub_uint32_t *block_size,

 			    struct ofdisk_hash_ent *op)

 {

   struct size_args_ieee1275

@@ -698,16 +713,6 @@ grub_ofdisk_get_block_size (const char *device, grub_uint32_t *block_size,

       grub_ieee1275_cell_t size2;

     } args_ieee1275;

-  if (last_ihandle)

-    grub_ieee1275_close (last_ihandle);

-

-  last_ihandle = 0;

-  last_devpath = NULL;

-

-  grub_ieee1275_open (device, &last_ihandle);

-  if (! last_ihandle)

-    return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "can't open device");

-

   *block_size = 0;

   if (op->block_size_fails >= 2)