[PATCH] Fix swsusp with PREEMPT

This fixes swsusp with CONFIG_PREEMPT and makes locking a bit more
obvious.

diff --git a/kernel/suspend.c b/kernel/suspend.c
index 1033ee3..3087358 100644 (file)
--- a/kernel/suspend.c
+++ b/kernel/suspend.c
@@ -692,7 +692,6 @@ static int suspend_prepare_image(void)
                printk(KERN_CRIT "%sCouldn't get enough free pages, on %d pages short\n",
                       name_suspend, nr_needed_pages-nr_free_pages());
                root_swap = 0xFFFF;
-               spin_unlock_irq(&suspend_pagedir_lock);
                return 1;
        }
        si_swapinfo(&i);        /* FIXME: si_swapinfo(&i) returns all swap devices information.
@@ -700,7 +699,6 @@ static int suspend_prepare_image(void)
        if (i.freeswap < nr_needed_pages)  {
                printk(KERN_CRIT "%sThere's not enough swap space available, on %ld pages short\n",
                       name_suspend, nr_needed_pages-i.freeswap);
-               spin_unlock_irq(&suspend_pagedir_lock);
                return 1;
        }
 
@@ -710,7 +708,6 @@ static int suspend_prepare_image(void)
                /* Shouldn't happen */
                printk(KERN_CRIT "%sCouldn't allocate enough pages\n",name_suspend);
                panic("Really should not happen");
-               spin_unlock_irq(&suspend_pagedir_lock);
                return 1;
        }
        nr_copy_pages_check = nr_copy_pages;
@@ -724,12 +721,9 @@ static int suspend_prepare_image(void)
         * End of critical section. From now on, we can write to memory,
         * but we should not touch disk. This specially means we must _not_
         * touch swap space! Except we must write out our image of course.
-        *
-        * Following line enforces not writing to disk until we choose.
         */
 
        printk( "critical section/: done (%d pages copied)\n", nr_copy_pages );
-       spin_unlock_irq(&suspend_pagedir_lock);
        return 0;
 }
 
@@ -808,6 +802,24 @@ void do_magic_resume_2(void)
 #endif
 }
 
+/* do_magic() is implemented in arch/?/kernel/suspend_asm.S, and basically does:
+
+       if (!resume) {
+               do_magic_suspend_1();
+               save_processor_state();
+               SAVE_REGISTERS
+               do_magic_suspend_2();
+               return;
+       }
+       GO_TO_SWAPPER_PAGE_TABLES
+       do_magic_resume_1();
+       COPY_PAGES_BACK
+       RESTORE_REGISTERS
+       restore_processor_state();
+       do_magic_resume_2();
+
+ */
+
 void do_magic_suspend_1(void)
 {
        mb();
@@ -818,8 +830,13 @@ void do_magic_suspend_1(void)
 
 void do_magic_suspend_2(void)
 {
+       int is_problem;
        read_swapfiles();
-       if (!suspend_prepare_image()) { /* suspend_save_image realeses suspend_pagedir_lock */
+       is_problem = suspend_prepare_image();
+       spin_unlock_irq(&suspend_pagedir_lock);
+       if (!is_problem) {
+               kernel_fpu_end();       /* save_processor_state() does kernel_fpu_begin, and we need to revert it in order to pass in_atomic() checks */
+               BUG_ON(in_atomic());
                suspend_save_image();
                suspend_power_down();   /* FIXME: if suspend_power_down is commented out, console is lost after few suspends ?! */
        }
@@ -1224,13 +1241,13 @@ void software_resume(void)
        orig_loglevel = console_loglevel;
        console_loglevel = new_loglevel;
 
-       if(!resume_file[0] && resume_status == RESUME_SPECIFIED) {
+       if (!resume_file[0] && resume_status == RESUME_SPECIFIED) {
                printk( "suspension device unspecified\n" );
                return;
        }
 
        printk( "resuming from %s\n", resume_file);
-       if(read_suspend_image(resume_file, 0))
+       if (read_suspend_image(resume_file, 0))
                goto read_failure;
        do_magic(1);
        panic("This never returns");