[PATCH 1/7] um: support dynamic IRQ allocation
Anton Ivanov
anton.ivanov at kot-begemot.co.uk
Mon Nov 30 06:26:18 EST 2020
On 23/11/2020 19:56, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg at intel.com>
>
> It's cumbersome and error-prone to keep adding fixed IRQ numbers,
> and for proper device wakeup support for the virtio/vhost-user
> support we need to have different IRQs for each device. Even if
> in theory two IRQs (with and without wake) might be sufficient,
> it's much easier to reason about it when we have dynamic number
> assignment. It also makes it easier to add new devices that may
> dynamically exist or depending on the configuration, etc.
>
> Add support for this, up to 64 IRQs (the same limit as epoll FDs
> we have right now). Since it's not easy to port all the existing
> places to dynamic allocation (some data is statically initialized)
> keep the low numbers are reserved for the existing hard-coded IRQ
> numbers.
>
> Signed-off-by: Johannes Berg <johannes.berg at intel.com>
> ---
> arch/um/drivers/line.c | 18 ++++++++++-----
> arch/um/drivers/mconsole_kern.c | 2 +-
> arch/um/drivers/net_kern.c | 2 +-
> arch/um/drivers/port_kern.c | 4 ++--
> arch/um/drivers/random.c | 2 +-
> arch/um/drivers/ubd_kern.c | 2 +-
> arch/um/drivers/vector_kern.c | 4 ++--
> arch/um/drivers/virtio_uml.c | 4 ++--
> arch/um/drivers/xterm_kern.c | 2 +-
> arch/um/include/asm/irq.h | 6 ++---
> arch/um/include/shared/irq_kern.h | 12 +++++-----
> arch/um/kernel/irq.c | 37 ++++++++++++++++++++++++++-----
> arch/um/kernel/sigio.c | 2 +-
> 13 files changed, 65 insertions(+), 32 deletions(-)
>
> diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
> index 14ad9f495fe6..2d68f58ac54b 100644
> --- a/arch/um/drivers/line.c
> +++ b/arch/um/drivers/line.c
> @@ -262,19 +262,25 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
> int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
> {
> const struct line_driver *driver = line->driver;
> - int err = 0;
> + int err;
>
> - if (input)
> + if (input) {
> err = um_request_irq(driver->read_irq, fd, IRQ_READ,
> line_interrupt, IRQF_SHARED,
> driver->read_irq_name, data);
> - if (err)
> - return err;
> - if (output)
> + if (err < 0)
> + return err;
> + }
> +
> + if (output) {
> err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
> line_write_interrupt, IRQF_SHARED,
> driver->write_irq_name, data);
> - return err;
> + if (err < 0)
> + return err;
> + }
> +
> + return 0;
> }
>
> static int line_activate(struct tty_port *port, struct tty_struct *tty)
> diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
> index a2e680f7d39f..6d00af25ec6b 100644
> --- a/arch/um/drivers/mconsole_kern.c
> +++ b/arch/um/drivers/mconsole_kern.c
> @@ -738,7 +738,7 @@ static int __init mconsole_init(void)
>
> err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
> IRQF_SHARED, "mconsole", (void *)sock);
> - if (err) {
> + if (err < 0) {
> printk(KERN_ERR "Failed to get IRQ for management console\n");
> goto out;
> }
> diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
> index 1802cf4ef5a5..2fc0b038ff8a 100644
> --- a/arch/um/drivers/net_kern.c
> +++ b/arch/um/drivers/net_kern.c
> @@ -160,7 +160,7 @@ static int uml_net_open(struct net_device *dev)
>
> err = um_request_irq(dev->irq, lp->fd, IRQ_READ, uml_net_interrupt,
> IRQF_SHARED, dev->name, dev);
> - if (err != 0) {
> + if (err < 0) {
> printk(KERN_ERR "uml_net_open: failed to get irq(%d)\n", err);
> err = -ENETUNREACH;
> goto out_close;
> diff --git a/arch/um/drivers/port_kern.c b/arch/um/drivers/port_kern.c
> index a47ca5376d9d..efa8b7304090 100644
> --- a/arch/um/drivers/port_kern.c
> +++ b/arch/um/drivers/port_kern.c
> @@ -100,7 +100,7 @@ static int port_accept(struct port_list *port)
> .port = port });
>
> if (um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
> - IRQF_SHARED, "telnetd", conn)) {
> + IRQF_SHARED, "telnetd", conn) < 0) {
> printk(KERN_ERR "port_accept : failed to get IRQ for "
> "telnetd\n");
> goto out_free;
> @@ -182,7 +182,7 @@ void *port_data(int port_num)
> }
>
> if (um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
> - IRQF_SHARED, "port", port)) {
> + IRQF_SHARED, "port", port) < 0) {
> printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
> goto out_close;
> }
> diff --git a/arch/um/drivers/random.c b/arch/um/drivers/random.c
> index ce115fce52f0..385cb08d7ec2 100644
> --- a/arch/um/drivers/random.c
> +++ b/arch/um/drivers/random.c
> @@ -129,7 +129,7 @@ static int __init rng_init (void)
>
> err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
> 0, "random", NULL);
> - if (err)
> + if (err < 0)
> goto err_out_cleanup_hw;
>
> sigio_broken(random_fd, 1);
> diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
> index eae8c83364f7..d4c39e595c72 100644
> --- a/arch/um/drivers/ubd_kern.c
> +++ b/arch/um/drivers/ubd_kern.c
> @@ -1204,7 +1204,7 @@ static int __init ubd_driver_init(void){
> }
> err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
> 0, "ubd", ubd_devs);
> - if(err != 0)
> + if(err < 0)
> printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
> return 0;
> }
> diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
> index 555203e3e7b4..e78a54ea72a4 100644
> --- a/arch/um/drivers/vector_kern.c
> +++ b/arch/um/drivers/vector_kern.c
> @@ -1271,7 +1271,7 @@ static int vector_net_open(struct net_device *dev)
> irq_rr + VECTOR_BASE_IRQ, vp->fds->rx_fd,
> IRQ_READ, vector_rx_interrupt,
> IRQF_SHARED, dev->name, dev);
> - if (err != 0) {
> + if (err < 0) {
> netdev_err(dev, "vector_open: failed to get rx irq(%d)\n", err);
> err = -ENETUNREACH;
> goto out_close;
> @@ -1286,7 +1286,7 @@ static int vector_net_open(struct net_device *dev)
> irq_rr + VECTOR_BASE_IRQ, vp->fds->tx_fd,
> IRQ_WRITE, vector_tx_interrupt,
> IRQF_SHARED, dev->name, dev);
> - if (err != 0) {
> + if (err < 0) {
> netdev_err(dev,
> "vector_open: failed to get tx irq(%d)\n", err);
> err = -ENETUNREACH;
> diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
> index a6c4bb6c2c01..f76b8da28d20 100644
> --- a/arch/um/drivers/virtio_uml.c
> +++ b/arch/um/drivers/virtio_uml.c
> @@ -412,7 +412,7 @@ static int vhost_user_init_slave_req(struct virtio_uml_device *vu_dev)
> rc = um_request_irq(VIRTIO_IRQ, vu_dev->req_fd, IRQ_READ,
> vu_req_interrupt, IRQF_SHARED,
> vu_dev->pdev->name, vu_dev);
> - if (rc)
> + if (rc < 0)
> goto err_close;
>
> rc = vhost_user_send_no_payload_fd(vu_dev, VHOST_USER_SET_SLAVE_REQ_FD,
> @@ -854,7 +854,7 @@ static int vu_setup_vq_call_fd(struct virtio_uml_device *vu_dev,
> info->call_fd = call_fds[0];
> rc = um_request_irq(VIRTIO_IRQ, info->call_fd, IRQ_READ,
> vu_interrupt, IRQF_SHARED, info->name, vq);
> - if (rc)
> + if (rc < 0)
> goto close_both;
>
> rc = vhost_user_set_vring_call(vu_dev, vq->index, call_fds[1]);
> diff --git a/arch/um/drivers/xterm_kern.c b/arch/um/drivers/xterm_kern.c
> index d64ef6d0d463..50f11b7b4774 100644
> --- a/arch/um/drivers/xterm_kern.c
> +++ b/arch/um/drivers/xterm_kern.c
> @@ -51,7 +51,7 @@ int xterm_fd(int socket, int *pid_out)
>
> err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
> IRQF_SHARED, "xterm", data);
> - if (err) {
> + if (err < 0) {
> printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
> "err = %d\n", err);
> ret = err;
> diff --git a/arch/um/include/asm/irq.h b/arch/um/include/asm/irq.h
> index 42c6205e2dc4..b6fa6301c75b 100644
> --- a/arch/um/include/asm/irq.h
> +++ b/arch/um/include/asm/irq.h
> @@ -24,14 +24,14 @@
> #define VECTOR_BASE_IRQ (VIRTIO_IRQ + 1)
> #define VECTOR_IRQ_SPACE 8
>
> -#define LAST_IRQ (VECTOR_IRQ_SPACE + VECTOR_BASE_IRQ - 1)
> +#define UM_FIRST_DYN_IRQ (VECTOR_IRQ_SPACE + VECTOR_BASE_IRQ)
>
> #else
>
> -#define LAST_IRQ VIRTIO_IRQ
> +#define UM_FIRST_DYN_IRQ (VIRTIO_IRQ + 1)
>
> #endif
>
> -#define NR_IRQS (LAST_IRQ + 1)
> +#define NR_IRQS 64
>
> #endif
> diff --git a/arch/um/include/shared/irq_kern.h b/arch/um/include/shared/irq_kern.h
> index 7cd1a10c6244..7c04a0fd3a27 100644
> --- a/arch/um/include/shared/irq_kern.h
> +++ b/arch/um/include/shared/irq_kern.h
> @@ -9,10 +9,10 @@
> #include <linux/interrupt.h>
> #include <asm/ptrace.h>
>
> -extern int um_request_irq(unsigned int irq, int fd, int type,
> - irq_handler_t handler,
> - unsigned long irqflags, const char * devname,
> - void *dev_id);
> -void um_free_irq(unsigned int irq, void *dev);
> -#endif
> +#define UM_IRQ_ALLOC -1
>
> +int um_request_irq(int irq, int fd, int type, irq_handler_t handler,
> + unsigned long irqflags, const char * devname,
> + void *dev_id);
> +void um_free_irq(int irq, void *dev_id);
> +#endif
> diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
> index 3577118bb4a5..b94c72f56617 100644
> --- a/arch/um/kernel/irq.c
> +++ b/arch/um/kernel/irq.c
> @@ -19,6 +19,7 @@
> #include <kern_util.h>
> #include <os.h>
> #include <irq_user.h>
> +#include <irq_kern.h>
>
>
> extern void free_irqs(void);
> @@ -38,6 +39,7 @@ struct irq_entry {
> static struct irq_entry *active_fds;
>
> static DEFINE_SPINLOCK(irq_lock);
> +static DECLARE_BITMAP(irqs_allocated, NR_IRQS);
>
> static void irq_io_loop(struct irq_fd *irq, struct uml_pt_regs *regs)
> {
> @@ -421,27 +423,52 @@ unsigned int do_IRQ(int irq, struct uml_pt_regs *regs)
> return 1;
> }
>
> -void um_free_irq(unsigned int irq, void *dev)
> +void um_free_irq(int irq, void *dev)
> {
> + if (WARN(irq < 0 || irq > NR_IRQS, "freeing invalid irq %d", irq))
> + return;
> +
> free_irq_by_irq_and_dev(irq, dev);
> free_irq(irq, dev);
> + clear_bit(irq, irqs_allocated);
> }
> EXPORT_SYMBOL(um_free_irq);
>
> -int um_request_irq(unsigned int irq, int fd, int type,
> +int um_request_irq(int irq, int fd, int type,
> irq_handler_t handler,
> unsigned long irqflags, const char * devname,
> void *dev_id)
> {
> int err;
>
> + if (irq == UM_IRQ_ALLOC) {
> + int i;
> +
> + for (i = UM_FIRST_DYN_IRQ; i < NR_IRQS; i++) {
> + if (!test_and_set_bit(i, irqs_allocated)) {
> + irq = i;
> + break;
> + }
> + }
> + }
> +
> + if (irq < 0)
> + return -ENOSPC;
> +
> if (fd != -1) {
> err = activate_fd(irq, fd, type, dev_id);
> if (err)
> - return err;
> + goto error;
> }
>
> - return request_irq(irq, handler, irqflags, devname, dev_id);
> + err = request_irq(irq, handler, irqflags, devname, dev_id);
> + if (err < 0)
> + goto error;
> +
> + return irq;
> +error:
> + clear_bit(irq, irqs_allocated);
> + return err;
> }
>
> EXPORT_SYMBOL(um_request_irq);
> @@ -480,7 +507,7 @@ void __init init_IRQ(void)
> irq_set_chip_and_handler(TIMER_IRQ, &SIGVTALRM_irq_type, handle_edge_irq);
>
>
> - for (i = 1; i <= LAST_IRQ; i++)
> + for (i = 1; i < NR_IRQS; i++)
> irq_set_chip_and_handler(i, &normal_irq_type, handle_edge_irq);
> /* Initialize EPOLL Loop */
> os_setup_epoll();
> diff --git a/arch/um/kernel/sigio.c b/arch/um/kernel/sigio.c
> index d1cffc2a7f21..5085a50c3b8c 100644
> --- a/arch/um/kernel/sigio.c
> +++ b/arch/um/kernel/sigio.c
> @@ -25,7 +25,7 @@ int write_sigio_irq(int fd)
>
> err = um_request_irq(SIGIO_WRITE_IRQ, fd, IRQ_READ, sigio_interrupt,
> 0, "write sigio", NULL);
> - if (err) {
> + if (err < 0) {
> printk(KERN_ERR "write_sigio_irq : um_request_irq failed, "
> "err = %d\n", err);
> return -1;
>
Acked-By: Anton Ivanov <anton.ivanov at cambridgegreys.com>
--
Anton R. Ivanov
https://www.kot-begemot.co.uk/
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