Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757716AbYHCPdE (ORCPT ); Sun, 3 Aug 2008 11:33:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756101AbYHCPcy (ORCPT ); Sun, 3 Aug 2008 11:32:54 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:57765 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755915AbYHCPcx (ORCPT ); Sun, 3 Aug 2008 11:32:53 -0400 Date: Sun, 3 Aug 2008 16:14:47 +0100 From: Alan Cox To: Yinghai Lu Cc: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , "Eric W. Biederman" , Dhaval Giani , Mike Travis , Andrew Morton , linux-kernel@vger.kernel.org, Yinghai Lu Subject: Re: [PATCH 21/25] serial: change remove NR_IRQS in 8250.c v2 Message-ID: <20080803161447.791705bb@lxorguk.ukuu.org.uk> In-Reply-To: <1217732365-16595-22-git-send-email-yhlu.kernel@gmail.com> References: <1217732365-16595-1-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-8-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-9-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-10-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-11-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-12-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-13-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-14-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-15-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-16-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-17-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-18-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-19-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-20-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-21-git-send-email-yhlu.kernel@gmail.com> <1217732365-16595-22-git-send-email-yhlu.kernel@gmail.com> X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; x86_64-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4066 Lines: 152 On Sat, 2 Aug 2008 19:59:21 -0700 Yinghai Lu wrote: > use small array with index to handle irq locking for serial port > hope 32 slot is enough Untested alternative approach 8250: Remove NR_IRQ usage From: Alan Cox --- drivers/serial/68328serial.c | 11 ++--------- drivers/serial/8250.c | 41 ++++++++++++++++++++++++++++++++++------- 2 files changed, 36 insertions(+), 16 deletions(-) diff --git a/drivers/serial/68328serial.c b/drivers/serial/68328serial.c index 381b12a..277b78d 100644 --- a/drivers/serial/68328serial.c +++ b/drivers/serial/68328serial.c @@ -66,7 +66,6 @@ #endif static struct m68k_serial m68k_soft[NR_PORTS]; -struct m68k_serial *IRQ_ports[NR_IRQS]; static unsigned int uart_irqs[NR_PORTS] = UART_IRQ_DEFNS; @@ -375,15 +374,11 @@ clear_and_return: */ irqreturn_t rs_interrupt(int irq, void *dev_id) { - struct m68k_serial * info; + struct m68k_serial * info = dev_id; m68328_uart *uart; unsigned short rx; unsigned short tx; - info = IRQ_ports[irq]; - if(!info) - return IRQ_NONE; - uart = &uart_addr[info->line]; rx = uart->urx.w; @@ -1383,8 +1378,6 @@ rs68328_init(void) info->port, info->irq); printk(" is a builtin MC68328 UART\n"); - IRQ_ports[info->irq] = info; /* waste of space */ - #ifdef CONFIG_M68VZ328 if (i > 0 ) PJSEL &= 0xCF; /* PSW enable second port output */ @@ -1393,7 +1386,7 @@ rs68328_init(void) if (request_irq(uart_irqs[i], rs_interrupt, IRQF_DISABLED, - "M68328_UART", NULL)) + "M68328_UART", info)) panic("Unable to attach 68328 serial interrupt\n"); } local_irq_restore(flags); diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index a97f1ae..7165e88 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -145,11 +145,14 @@ struct uart_8250_port { }; struct irq_info { - spinlock_t lock; + struct irq_info *next; + int irq; + spinlock_t lock; /* Protects list not the hash */ struct list_head *head; }; -static struct irq_info irq_lists[NR_IRQS]; +static struct irq_info *irq_lists[NR_IRQ_HASH]; +static DEFINE_SPINLOCK(hash_lock); /* Used to walk the hash */ /* * Here we define the default xmit fifo size used for each type of UART. @@ -1541,9 +1544,28 @@ static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up) static int serial_link_irq_chain(struct uart_8250_port *up) { - struct irq_info *i = irq_lists + up->port.irq; + struct irq_info **list, *i; int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0; + spin_lock(&hash_lock); + + list = &irq_lists[up->port.irq % NR_IRQ_HASH]; + i = * list; + + while(i != NULL && i->irq != up->port.irq) + i = i->next; + if (i == NULL) { + i = kzalloc(sizeof(struct irq_info), GFP_KERNEL); + if (i == NULL) { + spin_unlock(&hash_lock); + return -ENOMEM; + } + spin_lock_init(&i->lock); + i->next = *list; + *list = i; + } + spin_unlock(&hash_lock); + spin_lock_irq(&i->lock); if (i->head) { @@ -1567,8 +1589,16 @@ static int serial_link_irq_chain(struct uart_8250_port *up) static void serial_unlink_irq_chain(struct uart_8250_port *up) { - struct irq_info *i = irq_lists + up->port.irq; + struct irq_info *i; + + spin_lock(&hash_lock); + i = irq_lists[up->port.irq % NR_IRQ_HASH]; + while(i != NULL && i->irq != up->port.irq) + i = i->next; + spin_unlock(&hash_lock); + + BUG_ON(i == NULL); BUG_ON(i->head == NULL); if (list_empty(i->head)) @@ -2951,9 +2981,6 @@ static int __init serial8250_init(void) "%d ports, IRQ sharing %sabled\n", nr_uarts, share_irqs ? "en" : "dis"); - for (i = 0; i < NR_IRQS; i++) - spin_lock_init(&irq_lists[i].lock); - ret = uart_register_driver(&serial8250_reg); if (ret) goto out; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/