ALSA: emu10k1: don't deadlock in proc-functions

The functions snd_emu10k1_proc_spdif_read and snd_emu1010_fpga_read
acquire the emu_lock before accessing the FPGA. The function used
to access the FPGA (snd_emu1010_fpga_read) also tries to take
the emu_lock which causes a deadlock.
Remove the outer locking in the proc-functions (guarding only the
already safe fpga read) to prevent this deadlock.

[removed superfluous flags variables too -- tiwai]

Signed-off-by: Michael Gernoth <michael@gernoth.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/emu10k1/emuproc.c b/sound/pci/emu10k1/emuproc.c
index 2ca9f2e..53745f4 100644 (file)
--- a/sound/pci/emu10k1/emuproc.c
+++ b/sound/pci/emu10k1/emuproc.c
@@ -241,31 +241,22 @@ static void snd_emu10k1_proc_spdif_read(struct snd_info_entry *entry,
        struct snd_emu10k1 *emu = entry->private_data;
        u32 value;
        u32 value2;
-       unsigned long flags;
        u32 rate;
 
        if (emu->card_capabilities->emu_model) {
-               spin_lock_irqsave(&emu->emu_lock, flags);
                snd_emu1010_fpga_read(emu, 0x38, &value);
-               spin_unlock_irqrestore(&emu->emu_lock, flags);
                if ((value & 0x1) == 0) {
-                       spin_lock_irqsave(&emu->emu_lock, flags);
                        snd_emu1010_fpga_read(emu, 0x2a, &value);
                        snd_emu1010_fpga_read(emu, 0x2b, &value2);
-                       spin_unlock_irqrestore(&emu->emu_lock, flags);
                        rate = 0x1770000 / (((value << 5) | value2)+1); 
                        snd_iprintf(buffer, "ADAT Locked : %u\n", rate);
                } else {
                        snd_iprintf(buffer, "ADAT Unlocked\n");
                }
-               spin_lock_irqsave(&emu->emu_lock, flags);
                snd_emu1010_fpga_read(emu, 0x20, &value);
-               spin_unlock_irqrestore(&emu->emu_lock, flags);
                if ((value & 0x4) == 0) {
-                       spin_lock_irqsave(&emu->emu_lock, flags);
                        snd_emu1010_fpga_read(emu, 0x28, &value);
                        snd_emu1010_fpga_read(emu, 0x29, &value2);
-                       spin_unlock_irqrestore(&emu->emu_lock, flags);
                        rate = 0x1770000 / (((value << 5) | value2)+1); 
                        snd_iprintf(buffer, "SPDIF Locked : %d\n", rate);
                } else {
@@ -410,14 +401,11 @@ static void snd_emu_proc_emu1010_reg_read(struct snd_info_entry *entry,
 {
        struct snd_emu10k1 *emu = entry->private_data;
        u32 value;
-       unsigned long flags;
        int i;
        snd_iprintf(buffer, "EMU1010 Registers:\n\n");
 
        for(i = 0; i < 0x40; i+=1) {
-               spin_lock_irqsave(&emu->emu_lock, flags);
                snd_emu1010_fpga_read(emu, i, &value);
-               spin_unlock_irqrestore(&emu->emu_lock, flags);
                snd_iprintf(buffer, "%02X: %08X, %02X\n", i, value, (value >> 8) & 0x7f);
        }
 }