[PATCH v2 2/9] alpha: marvel: make use of raw_spinlock variants

Julia Cartwright
2017-03-21T22:43:02Z

The alpha/marvel code currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel. Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@ni.com>
---
v1 -> v2:
- Add hunk which properly initializes the spin-lock (via kbuild bot).

arch/alpha/include/asm/core_marvel.h | 2 +-
arch/alpha/kernel/core_marvel.c | 2 +-
arch/alpha/kernel/sys_marvel.c | 12 ++++++------
3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/alpha/include/asm/core_marvel.h b/arch/alpha/include/asm/core_marvel.h
index dad300fa14ce..8dcf9dbda618 100644
--- a/arch/alpha/include/asm/core_marvel.h
+++ b/arch/alpha/include/asm/core_marvel.h
@@ -312,7 +312,7 @@ struct io7 {
io7_port7_csrs *csrs;
struct io7_port ports[IO7_NUM_PORTS];

- spinlock_t irq_lock;
+ raw_spinlock_t irq_lock;
};

#ifndef __EXTERN_INLINE
diff --git a/arch/alpha/kernel/core_marvel.c b/arch/alpha/kernel/core_marvel.c
index d5f0580746a5..4300b1d1cf2c 100644
--- a/arch/alpha/kernel/core_marvel.c
+++ b/arch/alpha/kernel/core_marvel.c
@@ -118,7 +118,7 @@ alloc_io7(unsigned int pe)

io7 = alloc_bootmem(sizeof(*io7));
io7->pe = pe;
- spin_lock_init(&io7->irq_lock);
+ raw_spin_lock_init(&io7->irq_lock);

for (h = 0; h < 4; h++) {
io7->ports[h].io7 = io7;
diff --git a/arch/alpha/kernel/sys_marvel.c b/arch/alpha/kernel/sys_marvel.c
index 24e41bd7d3c9..3e533920371f 100644
--- a/arch/alpha/kernel/sys_marvel.c
+++ b/arch/alpha/kernel/sys_marvel.c
@@ -115,11 +115,11 @@ io7_enable_irq(struct irq_data *d)
return;
}

- spin_lock(&io7->irq_lock);
+ raw_spin_lock(&io7->irq_lock);
*ctl |= 1UL << 24;
mb();
*ctl;
- spin_unlock(&io7->irq_lock);
+ raw_spin_unlock(&io7->irq_lock);
}

static void
@@ -136,11 +136,11 @@ io7_disable_irq(struct irq_data *d)
return;
}

- spin_lock(&io7->irq_lock);
+ raw_spin_lock(&io7->irq_lock);
*ctl &= ~(1UL << 24);
mb();
*ctl;
- spin_unlock(&io7->irq_lock);
+ raw_spin_unlock(&io7->irq_lock);
}

static void
@@ -263,7 +263,7 @@ init_io7_irqs(struct io7 *io7,
*/
printk(" Interrupts reported to CPU at PE %u\n", boot_cpuid);

- spin_lock(&io7->irq_lock);
+ raw_spin_lock(&io7->irq_lock);

/* set up the error irqs */
io7_redirect_irq(io7, &io7->csrs->HLT_CTL.csr, boot_cpuid);
@@ -295,7 +295,7 @@ init_io7_irqs(struct io7 *io7,
for (i = 0; i < 16; ++i)
init_one_io7_msi(io7, i, boot_cpuid);

- spin_unlock(&io7->irq_lock);
+ raw_spin_unlock(&io7->irq_lock);
}

static void __init
--
2.12.0